Here's another way of looking at it. You might be able to fit more in if you want to do more upkeep.
I've got 16 Africans in a 75g and I'm running an AquaClear110 HOB filter. I've been checking my levels about every 3 days since they just got hastily moved there from my 125 when it decided to spring a leak. I was able to move the used media, decor, sand and 75g of the used water over into the 75g, so after the first day or so, my 'cycle' hadn't really lost any time. I say that only to give you a baseline on this. My point is, that on a tank that has already cycled, I've got 16 healthy and happy Africans in a 75g tank, going on now almost 3 weeks, and i'm only just last night starting to creep up to maybe .25ppm on my ammonia, and they're fed daily. I plan on doing a small WC tonight when I get home, but not bad for almost 3 weeks!! So yeah, I could fit more in there, but then I'd be doing water changes a lot more often!! Just something else to consider.