Pistons: Compression ratio differences.

I‘m searching the right piston kit (stock like) to use for my rebuild. My car is a convertible 1990 A/T .
Stock pistons are flat with 4 v. relief no dish .
Searching for catalogs I see the Sealed Power Hypereutectic H345P listed as Flat w/ 4valve relief.
In all catalogs the price range for the set is $75/ $90 and the compression ratio (with 64cc combustion chambers volume – the 64 cc data is allways present on pistons data, the 58 cc it’s a rare data…- ) is allways some thenth lower comparing with others flat pistons w/4 valve relief. H669 P (Fedral Mogul group also.. I think they are Speed Pro) are also Hypereutectic machine worked flat top pistons w/4 valve relief, but are rated 0.2 / 0.3 higher on compression and are $100 / ख़$120 higher in price!
The Question: H345P are lower in compression ratio for larger valve relief? Or these pistons are lower in C.R. beacause they (maybe) are deked 0.025” / 0.030” under cylinder deck? I don’t want pistons with deck gap if stock pistons are not…. (I don’t know if stock pistons are deked or not).. Can I consider H345P a standard replacement of my stock pistons?? Someone in the forum used thhese pistons?
Another technical question: If I use for my rebuild a Forged piston kit ( TRW /Sped Pro forged, Flat with 4 valve relief) which is the advantage instead a cast /hypereutectic??
Finally…. Last question… Could I utilize a flat top w/ 2 valve relief??

Thanks
Beppe

 

TTT

 

Ther's none that can answer to my questions?
Beppe.

 

surrender.... none know..

 

Try the Engine Mod section, people there might have the answer.