Things you can do to increase your "digestive absorption-capacity" are:
a) use the ascorbate form (it's only a slight improvement, but AA and _A are not identical and some prefer AA for other biological reasons)
b) use a micro-emulsified form (so the peyer's patches in the intestines are likely to absorb a bunch of it that way, seeing it as a lipid). There isn't yet any Science I can find yet done on the absorption diff on this format because it really just came around a few years ago, when Brooks Bradley was trying to come up with a way to do DIY liposomal. The DIY version is mostly emulsified, but partly liposomal just due to the nature of the lipids. This does (or should!) absorb better. I can take 1.5g at a time before flushing of AA/SA but if I use Emul-C (DIY-liposomal-C) I can take about 4g.
c) use a quality liposomal version. I've tried several different ones. I'm not rich, so not all of them. Best price and most AA in smallest dose both, that I've found, is Aurora brand see amazon. (I have nothing to do with that corp at all fyi, just a buyer.) I have taken 24g at a time of that and not flushed at all.
d) this goes for all of the above: take small doses frequently. Take it once every 4 or even 2 hours (if you were desperately ill I'd just make it 0.5-1hr) and break up a whole day of a good dose into that. Although I can take only about 3.5-4g emulsified at a time without flushing, I can take 2-3g at a time and take it 5 times a day and not flush ever.
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Yes, if the DIY was 100% liposomal you would not flush. However even the best-case estimate of it (and most likely aren't anywhere near this %) is about 79% which means there will always be some free AA in that route. Some plain AA is actually not bad, and if you're really desperate I'd be taking it in every format I could get it.
I buffer the DIY with potassium bicarbonate after the formula is done, since I need some P anyway and that means the fraction that is 'free' may absorb slightly better plus it kills most the sour. Then I stir in d-Ribose, which I also need anyway, this adds sweet. I use super-strong black tea as the 'water' base to dissolve the AA and then the same water to soak the sunflower lecithin. Bit diff approach than I used initially - and it still tastes VILE if you ask me, but either my body (which has told me in multiple dreams it loves it, calls it "the liver food and repair juice" LOL!) is helping me like it better so I'll take it more, or those little tweaks help.
The DIY stuff is micro-emulsified. Lecithin will create liposomes all on its own so it's also partly liposomal. But not fully and even what's encapsulated may, despite the sonicator, be too big to get past the liver. (Which really I consider fine, since the liver's where everything needs to start anyway.)
Bear in mind that the absorption capacity of venous C (SA and ringers, I assume is the formula, there's an official one online) is only about 30-33%. The kidneys vent the rest. So even a DIY micro-emulsified-semi-liposomal, if you are just willing to take it in a lot of small doses, can probably get as much or more as an IV approach.
Researcher Dr. Cathcart has a white paper online related to bowel tolerance of C for various illness states -- although bear in mind that was oral AA/SA dosage, but in many small doses, so much more % of them might have absorbed than normal. I once made a summary of his title, abstract, figures and table into a single meta-image you might find useful, here:
The image comes from a tiny free blog hypernutrient.blogspot.com where I've been putting a little bit of C info over time (haven't had much time).
Best,
RC