Hi OkLady! I had a flagstone patio installed last spring, so might be able to help a little. The stones my landscaper used weren't as thick as what you're using, but I wouldn't think that would interfere with the process. The first thing you need to do is make sure the ground itself is level~you may have to bring in extra dirt. When this has been accomplished, compact the dirt with a compacting tool(or stomping),making sure it's well compacted. Next is the base of sand, again well compacted. If you do not level and compact, the stones will be uneven, and could possibly crack when stepped on, although the thinner the stone, the more chance of this happening. You may need to add/subtract sand as each stone varies in thickness, so put your level on each stone. When you've completed all these steps it's time for the cement, which I would recommend, rather than leaving in sand alone. I have a pathway coming off my patio which I left this way, and now I'm regretting it. Weeds, as well as shifting stones is a pain in the butt! I'll be getting it cemented!!

I had my patio done in a semi-circle rather than a rectangle/square. Just something you may think about. Good luck!!! ;o)

"My bf seems to think we don't need gravel or small rock because the soil where we live is good enough."

He's maybe right. If that area is sandy, and drains well, it doesn't need the rock base material for drainage.

"Our goal is to have chairs & table on a stable surface. He says fill the stones halfway up with soil & mix in a concrete/sand mix."

If they are laid well they will be stable. If a stone starts rocking, lift it and reset it.

All the concrete/soil mix will do is block drainage and crumble.