"I want to find a source for the springs so that I can offer them to you guys!"
Wayne,
Try Century Spring in downtown L.A. (also huge website,
www.centuryspring.com). They have a huge inventory of springs, but you may have to have them custom made if they don't have one that fits off-the-shelf.
BTW, the early S distributor curve provides the majority of advance at relatively low rpm (10º static and ~20º distributor) for a total of around 30º crankshaft.
It'd be nice to have a distributor machine so one could verify and tweak the curve.
Sherwood