This is a great thread. I'll add my rambling thoughts.

I recommend getting a thyroid panel, if you haven't already. High/low blood sugar levels can impact thyroid and conversely low thyroid can cause high/low blood sugar levels.

Also - if you suspect autoimmune etiology of your SFN and poor gut health, there is an autoimmune version of the Paleo diet. I'm glad diet changes have been working for you.

A1C is not always a reliable marker in everyone. There is a variability for how long red blood cells live in different people. This might skew the A1C number, depending who you are. I think it makes sense to run multiple types of tests and to have them repeated, so all tests can be put into proper context. I think Glenn made a great point about the OGTT.

In terms of literature on Benfotiamine, all the studies done have been of a mediocre quality. This is true of many supplements. You will rarely see any multiple double-blind placebo controlled studies. Unlike studies run on pharmaceutical drugs, you won't see an accurate or lengthy collection of adverse events either.

What is even more difficult is assessing if any of the medical literature on any given supplement is relevant to neuropathy, because that is the angle that everyone on this message board has.

One study about Benfotiamine and neuropathy:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3329837/

It showed 300 mg of Benfo/day for 24 months had no impact on PN or inflammatory markers.

I don't have a lot of time today to search Pub Med or read the above study carefully. I can tell you from professional experience, don't just read the conclusions. Conclusions are often incorrect or over inflated. Read the methods and results - you will often find errors or see deficiencies with how the experiment is set up. The more you understand a given topic and start to read several studies, you will start to see flaws and deficiencies with how study conclusions are constructed.