Where can a civilian obtain centrifuge training/testing? Where can a civilian get high g-force training/testing in a centrifuge?  (Likely by paying.)  Preferably with and without a g-suit.  Preferably based in the US, maybe Canada.

I'm betting the US Air Force centrifuge in San Antonio, Texas, and Canada's military centrifuge in Toronto would laugh and/or hang up the phone if asked.

Crossing my fingers there's a private or educational facility that would be an option.
This is a tough one. I don't know of any civilian facilities (but it does not mean they don't exist). This is a bit of a shot in the dark but in my opinion you may want to contact NASA about the Ames Research Center 20-G centrifuge. If for no other reason than this is the only non military one that seems to exist. For what its worth high speed centrifuges are not that simple despite just being something that spins in a circle. The speeds that the unit spin at are extremely high to say the least, to do this with out ripping the whole thing apart requires careful balancing and construction so they are not exactly something you can build at home. Here is at least one company that is building them and installing them elsewhere in the world. They list a bunch of installs for other militaries that might be more open to a civilian coming in but who knows.