Well, benfotiamine does not have risky high dose postings anywhere I could find. Because this is fat soluble, it may be that you reach a steady state with it over time, so that systems may be saturated and not need so high a dose.

If you have the funds to pay for it then give it a try.
Regular thiamine is eliminated quickly (within 4 hrs ) thru the urine. The benfotiamine form lasts longer in the body.

Notice that there are not many recent posts on that link.
And all the early ones used 600mg, or more, but then that fact
no longer appears in the later posts.

Something so miraculous that it can cure TN, sciatica etc, would be picked up by doctors rather quickly. Yet benfotiamine remains in the diabetic neuropathy world instead.

I have no doubt that it is very useful... but I don't think it will work for everyone that same way. I think it will work best in people with errors in thiamine metabolism mostly. You will see if there are any benefits within the first month or two.