Don't put too much stock in the slighter higher RG of the Hyper Cell. Until very recently the Hyper Cell (solid) was the top, top shelf ball in Roto Grip's line. It has a ton of differential and about as strong a coverstock as Roto has put on a ball. Also with a strong mass bias number it's going to want to transition pretty fast. Strong ball.
Meanwhile the original Optimus (pearl) IS lower in RG, but doesn't have that super-strong cover or core asymmetry. Less diff, too. If anything IMO that cover can be over/under on a heavier condition. Optimus solid is a different animal, it didn't seem to go over too well but I'm not sure why.
Optimus wouldn't be my FIRST choice for a benchmark ball (I like a mid-range hybrid or solid for this slot, myself) but as a medium-heavy kind of ball it's not bad either. It comes polished but actually seems to work great with some surface too, don't be afraid to experiment!
Based on the core numbers and the surface materials, I think that you will find the the Hyper Cell will actually be your middle (benchmark) ball, with the Optimus being more for heavier conditions and the Ascent Apex for drier conditions. Your 4X4X2 drilling is pretty strong, and is a good layout for most medium rev/medium speed bowlers. I would recommend sticking with the same layout for all of the balls so that you can see the actual differences between them which makes on-the-fly ball change adjustments much easier. You can also adjust the surfaces to move them further apart or closer together.