Does anyone have detailed pictures or diagrams of a CAR stock disassembly?

I'm trying to see if my postban stock has any conversion potential. It looks like I have a tube with a single tapped hole on the bottom. I then I have the plastic stock shell, a "handle", and a hex-headed screw running through.

I'm mostly confused about the source of the spring pressure I usually feel on the real deal.

Here's a diagram from Colt.

Some of those fixed post-ban stocks aren't fully fuctional. For example, the spring pocket (for the latch pin) aren't formed in. Also, you'll probably need to change the buffer tube. Some companies use a Rifle buffer and spring instead of a Carbine buffer and spring. You might as well get a complete kit, it would be easier in the long run.

Well, I think I found a place to get the correct metal hardware.

I like the CAR stock, but the M4 stocks have more positions. Anyone know if a CAR stock will fit on a 6-pos. M4 buffer tube? If so, will it also extend out further than an A2, as with using an actual M4 stock?

The number of positions depends on the receiver extension tube (part #5 above),  not the stock.   As long as your CAR stock is mated to a compatible diameter tube, you can mix and match to your heart's content.

Which usually means Colt, LMT, and Vltor are compatible (aka "Milspec"),
and all the others mix with each other only.