I've got a 40" KRA stack full length drawers on the top box and split drawers in the bottom. Depending on how many tools you have probably drives the best solution. My stack is for home use but I have a shallow, semi and deep in 1/4, 3/8 and shallow and deep in 1/2 in both metric and imperial, metric and imperial spanners and a bunch of other stuff.
The problems I have found are that the split drawers in the bottom are just not wide enough to store much, long ratchets and breaker bars just don't fit unless diagonally which wastes a drawer. It only has one single full length drawer on the bottom which is stuffed with the smaller sockets and extensions. The full length in the top chest are far more useful to fit the range of spanners screwdrivers etc.
Having the odd smaller drawer is useful for items like drill bits, taps, electrical connectors etc
If you only go for a KRA they are only 20" deep. When browsing through the posts here you see other boxes and think that looks organised. I'll move my stuff around to match, and then realise that you can't as most boxes on here are at least 24" deep if not 30" for the Epiqs.