For b12 I would use 5g of Metylcobalamin a day.
For b1 I would chose Benfotiamine 200mg, 3 times a day.

Both don't need to be converted to be used by the body. Plus Benfotiamine is lipid based so excess can be stored. Thiamine is water stored, so too much and the body just flushes it out like an other water base vitamin.

I haver got neuropathy partly from alcohol consumption, so I definitely sympathise. Although my feet have a lose of sensitivity it my left hand that is starting to go 'claw like'. Guess which hand I write with! I am off to the specialist this Thursday, which will possibly lead to some form of surgery. Take care.