the hemi killer cams on my chart have eather to much lift and or duraton for the stage 1 spring, i think that it is about .520 lift that you should go to heavyer spring and or around .240 duration. T.A. has a single spring that i think is good to .550 lift, that way you dont have to remove your heads and pay the extra $100 to have the spring seat cut for dual springs. i would call T.A. and talk to them, also they might be o.k. but i wouldnt take a change on useing to weak of a spring.
sounds like you are on track, you need to also match the cam to your setup, most of the himi killer cams need around 355 gears, at least a 2000 stall and some head work to take advantage of the lift. it is always best to buy the cam the manufacture thinks is best for your setup. to much cam in a car that isnt set up for it will make it slower.
