LA’ing a Magnum

Roller size; I pick up what you’re putting down
Compression; Isn’t that primarily from chamber differences?

The deck height is supposed to be different between mag and LA

I don't know what you mean "pick up what you are putting down". It takes more spring to put them back down, simply put. They are heavier. My new engine is a LA roller and they may or may not come back out of there, later on