Thanks Tony. for the advice i bit confused on what you are saying. Are you saying that if i took out the featherfins it would be a good set up?
My tank volume would be 270 US gallons
Damn! 270!... even yummier.
Welp, here's what I would do, based loosely on your stocklist.
Without Frontosa:
Several rock piles, each for a pair of rock dwellers (start with 4-6 of one type of calvus/comp, one type julidochromis, one other "non-invasive" type, or maybe group of larger shellies). A large group of paracyps would be neat. They are sort of in-between rock-dwellers and open-water swimmers. Get a few pieces of tall slate and lean them up against the back/sides of the tank to make tall caves where they will sleep - all bat-like.
Leave enough open sand and go with a sand-sifter. I'm sort of new to those guys, but a good non-angry species is E. kilesa. A tank that size will be more than sufficient for them.
Lastly, get a large group of Cyps. I've heard that certain jumbo sp. can be extremely aggressive, so you may want to check into differences between species/locations. I have Cyp leptosoma Utinta in my 125 and love them - they are one of the smaller ones though. Shoot for 18 or so.
If you went with that grouping, you could even swap out the Paracyps for the featherfins if you'd like. Just stick with less aggressive other stuff (non-aggressive Cyps, smaller Julies, etc). If you are interested in doing this though, make sure to pair the feeatherfin species with the sifter as they both range greatly in aggression. I have O. nausta and Callochromis in my 125. They're both still smallish, but are working so far.
Frontosa:
Go with a large (20+) group of one kind of frontosa (any kind will interbreed with any kind) along with a group of Cyrtocara moori. I know folks will probably disagree, but a cool addition would be a group of large barbs - tinfoil or torpedo would be really cool, stay towards the top and probably not get eaten. You could try comps/calvus, but it is only a matter of time before they become expensive lunch. (I have seen pics of 5 inchers bitten clearly in half).
Again, I'm no expert in Tangs, but know that the above options should work well.