If this is one of those not eating much yet, it's probably not such a bad thing for now. Cyphotilapia get to be chunky fish, but they shouldn't look roundish. In any case they can go a while without eating much, so if a couple are a little slow getting acclimated it shouldn't be a problem. It's not unusual, really.
I don't know that I can precisely describe feeding amounts, it also depends on what you're feeding, size of pellets, etc. I tend to think in terms of a pinch or two at a time, which makes sense to me as the one doing the feeding but not precise. What I can tell you is I feed according to body profile, fish looking a bit skinny and I add a bit, but if they start to look round I adjust down a little. Getting them all the same doesn't always happen, but for the most part fronts should have a flat lower profile, not rounded out underneath. Not so flat at a small size is okay, kind of like a bit of baby fat, though it's not really the goal and by the time they're 3-3.5 inches I didn't want mine looking rounded. What you don't want is a bulging belly area, not healthy for them at all, can cause bloat, fatty liver, etc. An adult female carrying eggs is the exception.
I mainly do two things trying to distribute food evenly when some eat more aggressively than others, keep pellets small enough that a single fish can't gobble up a lot too easily and (for lower level feeders like Cyphotilapia tend to be) put food close to filter outlets to blow it around and make it sink faster.
...Some people don't like small fish in a big tank, but I don't mind it. To me it's closer to scale in the wild, so I actually enjoy that stage.
ken31cay
for recommending them, and to
neutrino
for all your help, as well. 
