Alright just to start I did a search and didn't find the answer I was looking for. I'm assembling an engine with a flat tappet cam that will be using dual coil valve springs. I have done a lot of reading and the concensus seems to be that the proper way to break in this type of cam with dual springs is to remove the inner spring, break in the cam, then replace the inner spring. The problem I am having with this is I have found it dam near impossible to get the dual coil springs off my heads before they are even on the engine. The screw type vavle compressor, with the 2 arms on it does not reach to the inner spring, and I have already bent one of the other kind of comresssors that goes all the way around the head and presses on the other side of the valve. I plan to get a better made one of those to initialy remove the springs and replace the valve seals. The issue is how do i compress the dual springs to install them after I break in the cam? I will not be able to use the same type of valve spring compressor since the heads will be on the engine and hopefully still in the car. I have found one other type of spring compressor, which appears to screw down on the rocker studs and compress two springs at once. But i'm afraid to try that in fear of doing damage to my heads or bending the hell outta the tool after I just sprent 100 bucks on it. Any suggestions?

Cheap old lever-style compressor has always worked for me, along with running compressed air into the cylinder through the spark plug hole to hold the valve up. No need to grab underneath of the valve spring. Compressed air hold the valve closed, lever compressor pushes down on the top of the retainer.

Sometimes you have to give the retainer a couple small whacks with a mallet to pop loose the retainers from the valve stem, but other than that it's fairly straight-forward.