What type of stone?

I have a pole building that I'm trying to upgrade. It was built and used as a stable and arena. I'd like to convert it to shop/storage as money allows. My ultimate goal would be to have a concrete floor throughout. I recently spoke with a concrete guy about this and he initially recommended I start with #11 stone as a base for my concrete. When I suggested I might want to use the facility with the stone floor for a few months or longer, he changed his suggestion to putting down #73 stone. He said it would work as well as a base for concrete if/when I got to that point but would be far better as a floor until I got ready to pour.

What I know about stone and it's applications is just about nil so I wanted some input and some explaination as to what to use and why. I'm not questioning this fellow's knowledge or anything but would like other opinions as well. As I said, my eventual goal would be to have a poured floor but finances won't allow it to be done now or probably in one pour whenever I do start pouring.

The area in question was used as an arena and is 40'W x 80'D. I'd like to use the front 24' or 32' of that as a shop/equipment storage area now (the 8' difference would gain me a side door 8'W x 12'H). My options, as I see them at this point, are to just stone the front area (be it 24' or 32') now or to stone the entire 80' depth now. Any suggestions or ideas on how I might do this differently or better are certainly welcome.