I think the RPM intake would provide more mid-range and fit your application best. Either the 528 or 557 MP cam should do fine... its a matter of "personality". Both have pretty long duration but the 528 should have better manners than the 557 and maybe a bit better fuel consumption if that matters.

It sounds like you will have perfect "quench" with zero deck... even so 11:1 may be pushing it on pump premium. The bigger cam may resist detonation better.

I personally like solid flat tappet's... make sure lifters are free to spin, assembly lube well, start up fast and run high zinc oil and there should be no problems.