I don't have any 4-drawer banks, but the 2 bottom drawers on my 3-drawer banks are the same depth. I haven't wished that they were otherwise. Have you measured everything you have that you might wish to store? The only problem I ran up against in the beginning was that my food processor was 1/4" taller than any drawer I had...But it died and my new one fits. Anyway, that would be the only reason to make any deeper than the 10 1/4"...if you want to store something that's taller. I think if you get the bottom drawers too deep and make others shallower, that you might end up stacking too much in the deeper one. It's all just my opinion and experience, so I hope it helps.