Compared to drugs, dosing often times does not translate well to the most effective use of herbs. This said, Schulze, like Christopher before him, were constantly being asked about dose. Each of them had a fairly consistent routine for broaching the dose question. Just to be clear, I'm not telling you all of this with the intention of talking down to you, just reciting what I've heard these two men say many times.
First thing to remember is that dose in the context of "take this precise amount every _____", be it this pill twice a day, that pill every 6 hours, does not translate with taking herbs / herbal formulas for medicinal purposes. As such, the recommendations for herbs does not use the same kind of one-size-fits-all approach, it factors in plenty of leeway for differences likely to be encountered from one person to the next as well as one moment/condition to the next, like, how you felt in the morning versus early afternoon versus evening.
Second thing to be aware of is that both Schulze and Christopher would provide guidelines for taking amounts of herbs/formulas during times of illness, and would have different guidelines for taking amounts for routine/maintenance purposes when ongoing illness was not prevalent.
Third thing to be aware of is that both men would first give a sample amount of an herb/formula to be taken, followed with the advice "pay attention, listen to your body, monitor your own condition". The idea here is that the person taking medicine is the one to be in the best position to know how their body is responding to medicine and as such this person should learn how to develop a feel for knowing when they might consider increasing or decreasing either the amount or frequency of taking the herb/formula for desired effects.
Off the top of my head, there are several other pieces of dose-related advice these men often recited, I don't remember all of them, but one of these is that depending on the form the herb/formula is being taken in, this will also impact how much of it a given person needs to take. You mentioned taking raw garlic cloves. This is not a hard & fast rule, but raw garlic cloves is the form that would generally be advised for a long term daily/maintenance approach. You, on the other hand, seem to be trying to address a specific illness/disease, namely your body's fluctuating blood-sugar level. You mentioned marginally high BP, but without knowing other factors, the BP you mentioned does not look high to me... it might look high to a doctor, but not me :)
Anyway, if you want to continue with taking raw garlic, the amount and frequency you've been using has undoubtedly had little if any noticeable impact on your sugar levels. Two basic choices here: 1) increase the frequency from 1-2 cloves pressed in OJ from once a day to twice a day, perhaps once in morning and once in evening.... monitor the situation, adjust accordingly; 2) switch to a different form.
Without knowing the exact reference / interview in question, there is a potential clue you provided: ".... Schulze interview on another site talking about garlics immediate effects to reduce blood sugar..". Be aware, I am not an expert, not a formalized health practitioner, and am not even so much as a doctor, so I cannot and will not prescribe medical advice to you. OK, enough with disclaimers. My hunch that Schulze may have been implying the use of Garlic Tincture Why? Because you quoted him as indicating immediate effects
Because tinctures are often made with alcohol, their effects are often immediate. Alcohol absorbs directly through the lining of the stomach and into bloodstream. Alcohol that has been infused with herbs - like garlic, will absorb directly through the stomach wall, into your bloodstream and the effects will be immediate. If you were to try a garlic tincture, the general advise on "dosing" would be to start off conservative, pay attention, monitor yourself, listen to your body, and then adjust amounts and or frequency accordingly. A conservative amount of garlic tincture to start off with would be anywhere from several drops to perhaps a half dropper to a full dropper. Try that, let it go for several hours, monitor, listen, and if nothing discernible occurs, take the same amount and continue to monitor; repeat. If you get to be a day or two in and no discernible results, increase the amount taken from say, 1/2 dropper to a full dropper, or from a full dropper to 2 droppers, wait several hours while monitoring, if all okay, repeat the amount.... OR, you may find the need to reduce the amounts/frequencies. Only you can know best. Some people might require 1/2 dropper 3 times a day. Some people might need 2 droppers twice a day. Some people might need 3 droppers 5 times a day. These are not "drugs", these are herbs with medicinal properties, no two people are identical, no two people will have identical effects from identical amounts. This brings me to the final, off-the-top-of-my-head advice from Christopher/Schulze as it concerns how to go about determining the amount and frequency of herbal dosing that is right for you.
If you are currently taking prescriiption medications, any meds on a routine basis but especially meds for sugar, all bets are off and you are sort of on your own to chart these potentially murky waters. This is nothing personal, per se, against people on meds. The problem is, prescriiption meds, all by themselves, are their own can of worms, subject to producing wide ranges of effects, some undesirable, some desirable, and these might be worsened "interactions" when herbs/herbal formulas are introduced, and regardless of the actual causes, herbs will most likely get the blame. Because of this, the best advice from the view of an herbalist who does not have the advantage of seeing / treating the person in-person is to tell them the above paragraph and wish them well. If you know a person who has a background with herbs and they are willing to work with you in person, you will stand a much better chance of navigating these situations in ways that not only keep you alive but improve your condition AND, longer term, helps to get you off the prescriiption meds.
Within the last 6 weeks I was involved with a drug/herb interaction scenario. The basic scene was, a cooked a batch of fresh-brewed Cayenne-ginger tea and served it to 3 other people plus myself. Except for me, the other three are elderly folks, two 79, one 92. The one 79 also happened to be on sugar medications for treatment of "Type II Diabetese". They were the only one of the four to experience a negative reaction. They spent about 4 hours in what I characterize as moderate to severe shock: sugar spiked to over 300; week, woozy, sweating, blurred vision, unstable on feet. For the last 3 - plus years, their problems with sugar have always been that it sags way low, like, 50, 60. They never had a spike anywhere close to this. For them "bad level" is like, 160. After the fact I did find some literature on line that advised "do not take ginger if you are taking any of these meds (a short list of various patented/commercial pharma formulas) for treatment of NID Type 2 Diabetes".
Just to recap, perhaps try upping the amount and or frequency of raw garlic. Consider the potential benefits of tincture. Good luck.