You make some very good points for your decision and your personal use of Metformin. As you can tell, I tend to believe that nature has the answer for MOST conditions and likely has even more answers that we simply have not discovered yet or that has perhaps been forgotten due to the suppression of natural alternatives.
When I refer to "nature", I normally mean much more than just taking vitamins, mineral or other supplements. Healthy diets and exercise are usually vital parts of any successful natural protocol. Sometimes high blood sugar can be complicated, if not caused, by other underlying problems, such as improper diet, obesity and a sedentary lifestyle - all of which must be corrected in order for nature to have the best chance of success. Certainly, those dangerously high high blood pressure levels you mentioned of up to 500 (at that level one should be in emergency medical care!) are most often seen in diabetics with improper diet and weight problems.
Without knowing more about your physical condition, diet and lifestyle, it is hard for me to comment on what other things you might do. Possibly your fasting blood sugar levels might benefit from the beta glucans and fiber in this product and information at Life Extension: http://www.lef.org/magazine/mag2007/jul2007_report_blood_sugar_02.htm
I am glad to hear that you are improving, regardless of any other considerations!