I'm using the stock Trick Flow valve springs right out of the box. Cam is 271 at 050 with .460 lobe lift so gross valve lift is 0.690 with the 1.50 rocker arms.
Trick Flow says the springs are good to .700 lift so I put a .700 lift cam in it. I did swap out the Ti retainers for a set of steel retainers so the flat damper wouldn't chew up the Ti. So far I don't see any problems at 7000 rpm with the steel retainers.