what kind of cable winch should I use?

Yikes, the bad news is that4 come-alongs would be expensive...the good news is I've already got two of them...but the bad news is that even buying two would be expensive. But maybe you're right, Jimacuda. Come-alongs might be the way to go.
When I removed my 33 Plymouth coupe body from the frame I did what you are planning with the 2x4's but I made a frame, ish structure that I could bolt / screw to the body that kept it from being able to move on the wood. The come-along or the gear wenches seem good but watch the little catch latches. Sometimes they are finicky. Good looking Touring. Good luck