Front spring and shock recommendations

I have 620s right now with one coil cut off and Koni adjustables. With it right now bouncing on the front end I can only make it move about an inch. I don’t run a sway bar and with the springs I have now the springs come lose when I jack up the front end. Now that I'm getting more into drag racing and will have better tires soon I want a spring that won’t come unseated if there is much weight transfer. I can only seem to find 620s or 240s which says racing only, nothing in the middle. The 90/10 shocks are also racing only but it seems that people say they are fine on the street and highway.

Has anyone used the Summit brand adjustables? I don’t drive the car enough to need an expensive shock, the Summit ones are only $26. Is the quality between say the Lakewoods and Summit even noticeable?
For the springs...The California Mustang catalog I have says anything smaller than a big block uses the same spring. They list a heavy duty and a standard though. Since I had to cut the 620s to get the right ride height are other springs going to be long enough to cut and not come lose or will it sit lower with a different spring rate and I might not have to cut them?