Needs some wisdom thrown my way.

First you got dicide which heads you plan on buying down the road ? So you can buy pistons that give you the desired CR.
And to figure out desired CR you also need to firgure out which cam will be used with the new heads.

How much power you ultimately looking for ?

440 with Trick Flow heads 10.5:1 and hydraulic roller can get you over 600 hp and being a pretty simple build. Even lesser aftermarket heads get get you over 500 hp.