Cinder block and insulation, eh?
It’s time to take 1 giant step backward. You’ll find that unfinished basements are very dirty, and that the dirt gets on your layout. Step 1 is to put up drywall. If you have cinderblock all the way from floor to ceiling, you can get away with painting the block below the layout level, but putting up drywall above will give you a good surface you can paint a backdrop on directly.
Don’t forget the floor and ceiling, too. If you need to access plumbing and wiring, then consider a drop ceiling. It’s not expensive, and it goes up quickly. Think about good lighting while you’re at it, and also electrical outlets before you do the drywall.
Finally, do something about the floor. If it’s concrete, it will put up a lot of dust. Garage floor paint is good enough, but just do something about it.