What do you mean by "correct" compression rate?

In old times there was a lot of talk about higher duration cams "needing" more compression, but during the 90s it was proved you make more power, regardless of compression ratio.

The GX cylinder heads have larger chambers, so compression will drop a bit compared to the "premium gas" GX engine. You should have exactly what the "regular gas" GX (twin carb) engine had. All factory stuff, the camshaft seems similar too. See A12GX Engine