cold setting experiences?
 

I just worked on bending the rear end of a misaligned frame. From what I've read of this it didn't go as expected. Before using the sheldon brown 2x4 method I just tried pulling apart at the dropouts with my hands and was so surprised to see it go from 123mm to 132mm that I thought I'd measured wrong. I pushed it back again with my hands, not too hard, and it was back around 123mm. After some fiddling with the 2x4 I did get things pretty centered and at about 130mm, but considering the lower than expected amount of force and "springiness" to get it there I'm wondering if this is normal or if it indicates damage and if I can expect it to stay in this alignment. The frame has sv980 stamped in the main tubes and I think it's a pugeot race bike.

It's probably fine. Bike rear stay vary tremendously bike to bike with some being very stout and some more pliable. There's also a difference in the bending properties of various metals and tempers. Mild steels spring a very short amount before bending, alloy steels can be very springy, resisting bending and returning to original dimension even after flexing a decent distance, yet once they start bending it's easy to go too far.

Once you've got it where you want it, it'll stay that way until there's enough force to exceed it's flexible range and bend it anew.

BTW- next time around try to control the way you cold set (bend, in fancy terms) the stays so only one moves at a time. Then you can take each half the distance, and make sure the center line is maintained.