I have played around with Moonshot quite a bit in OR. Building it as a two-stager turns out to be tricky.
If it's staged 18mm->18mm, then it really struggles to get off the pad. I just can't get it mass low enough, and it's a sure bet that the rocket would end up heavier than the OR model anyway. Given that the rocket has not one but two rings, it's possible it would stay straight even on a slow launch, but I just wouldn't feel good about it.
It could be two-staged, 24mm->18mm, although then I have annoying retention problems in the booster. That could send it up to about 1000' on a D12-0 -> C6-3, which would be a pretty nice flight although I may never find the booster.
If I revert back to a single stage, 18mm, then it shows up to something like 500+ feet on a Q-jet D. That's probably OK, this rocket wouldn't exactly be intended for performance anyway.
But I just don't feel conviction about any solution, so I'm going to hold off on it for now. It'll go right to the front of the build queue as soon as I make a decision. On to other things in the meantime.