Retune my entire carb after installing new heads?

I didn't notice any difference on the butt-dyno in low- and mid-range performance when I went from an 800 to a 950 (once I dialed it in). But a smaller carb may cost enough power that it kills some of the increase from going to good heads!

This is the first I've ever heard of "compression time"... not to say it isn't a thing, but isn't that why lower compression and less dense fuel mixtures benefit from more advanced ignition timing?