Hi Mark, people with alcoholic Neuropathy are normally very low on B1 too, I believe Benfotiamine is pretty potent form of B1, i haven't used it myself though, i can't see the need for it, i do take 200mg daily Thiamine daily, which really should be plenty anyway.
I think B1 is a very safe supplement, the only time i don't take my thiamine is when i am on antibiotics, B1 should not be taken at the same time as the antibiotic tetracycline because it interferes with the absorption and effectiveness of the medication.

Brian