Two hours after eating will still have food in the stomach for most
people. IF you have fiber of any kind or fat it will take up to 4 hrs to pass in some people. The Oxy will slow things down too.

If you get up in the night to go to the bathroom, you might take the B12 and lipoic at that time.

If you are getting good results with the benfotiamine, you could try cutting back to see if it holds. I think the enzymes may get saturated after a while, and you may not need that high dose for longer periods. It is mostly a matter of expense. Benfotiamine doesn't show much toxicity reports, so I think it is probably okay for now. But I am a firm believer that if you no longer need a certain dose, you can cut back some and see what happens.

B12 seems to be for life because of the factors that inhibit its
absorption. The benfotiamine is somewhat different. It works on certain enzymes that thiamine uses, and absorption or blockage doesn't seem to show up in the studies, so whatever dose works for you is what you stay with. I don't take 300mg anymore as 150mg seems to work as well for me. There are even some days I don't take it at all, since it has been years I've been using it.