I pushed my a arm all the way down and got my springs out as well. You can go to a local Autozone/Murray's, if they have those in your area, and rent a spring compressor - free after you return it.
As far as how much to cut, I started with 1 coil then put it back together. Was way too high for my tastes, so i took the springs out and cut a little more, and again put it back together. Finally on the third try, I got it exactly where I wanted it to sit. Its under a coil and a half. Anymore and it would be slammed. I haven't had any problems what so ever with my drop as I stated before. I also have NO iso's front and back, and have no squeaks either. Guess it depends on the car and what kind of condition its in.
Start with 1 coil and go from there.