i have the comp cams springs (26113-16), there good for .550 lift, i think they have 93lbs seat pressure, and 198lbs open pressure, i havent even ran the engine yet so i cant say anything good or bad, but thats what most people go with..
buy the hitech stage IIs and you dont need springs plus you can make 300rwhp without losing any low end torque granted you have long tubes. i have manley nex tek springs in my new heads. they have been a great spring for high rpm. havent hread any issues either. cheap also. good luck on the install its a pita with the motor in the car.
I can only comment on what I've had. I originally went with the comp cam springs and in 4 months they were allowing the valves to hang open. I was revving the car to 6800. I eventually switched to crower stage 2 with titanium retainers and had no problems after that. That was with stage 1 cushman cams in the car.