[Jeff Lee]

You will typically have a smaller wire diameter and more coils to be optimum. The smaller wire diameter makes the coil spring "softer". This allows the weight of the front end to compress the car more at static height than the V8 springs it came with.
The purpose of having additional coils is to get the spring to recoil (if that's the correct terminology) once you launch the car.
So you have this soft, small wire spring that is ready to recoil to it's free standing height once the car is launched. That will promote a higher front end height which aides in weight transfer & traction.
Using a thicker wire will have the opposite affect unless of course your front end weight is much heavier.
The bottom line is you need the spring compressed as much as possible and once you launch it recoils and off you go.
Also, shortening the spring, any spring, for the "right" static height creates a stiffer spring rate and will not help the situation.
I tried every factory AMC spring available from V8 with no a/c to 6 cylinder springs. I eventually went to a custom set and even that took a few sets to get it the right ride height and launch characteristics. A quality set of springs will last a very long time. A cheap set will not.
Hope this answers your questions.