Can I go 24 inches deep with 304 gravel for a garage floor as long as I roll it every 3 inches or so.

Generally 57 gravel would be used for this and you wouldn't need to roll or compact it (although I would at least hand tamp it around the edges). I would think that you should be all right with 304 if you're using a vibratory roller in 3" to 4" lifts. I would also prefer 57 because it gives condensed water a place to go from the bottom of the VB. Check with inspector if they are going to approve it before pour.

Why so deep? Sounds like a waste of material but maybe I don't really understand what you are building. What is the thickness of the concrete slab.
What type of soil?
I inspected interstate and state highway construction and have never seen a base course of such depth. Maybe to try and "bridge" over some questionable soil but even that is done usually with a good soil fill. 57's are good for handling underground water (if that is the case) but you need an outlet or you have built a bathtub. I think we need more information and if I accomplish nothing else, maybe I can encourage that much.