New Tank, New to Cichlids

Hi,

Considering the setup of a new 55G with Africans. Kept lots of SA
cichlids and community tanks as a kid but no Africans. Just a couple
of questions to ground myself:

- Do Africans like a lot of cover in the tank? I'm big into rocks and
stuff and building little caves and overhangs...that a good
environment?
- In a 55G I was considering an Emporer 400 for filtration. Would I
be better served by two Emporer 280s to provide backup and to provide
water movement in two plces in the tank?
- Do Africans like water movement? I usually like to hide a powerhead
somewhere low and shoot the output towards the surface. Would that
bother them?
- Would the dimensions of a 65G be better in this case? 55s are cheap
and ubiquitous...but tall and thin.

Thanks all, I appreciate any help.

-Keith