That's a good idea, i need to get one as well.
Unfortunately i've been a bit too optimistic about the b-complex. This afternoon i had a few undigested bowel movements and intestinal cramping. Oh well, back to the drawing board.
I'm having some success with biotics research Bio-B 100
This is high quality LOW dose B-complex, you need to take 3 tablets to get to 100% RDA, so one tablet contains 33% RDA, perfect to start with and then build up the dose gradually.
https://www.pureformulas.com/biob-100-180-tablets-by-biotics-research.html