Matt51- in response to your post-
My full-centrifugal 3-disc 8" CrowerGlide does NOT use release springs. The only setup variables consist of how many weights (0 - 6, they resemble 1/4" thick small-diameter flat washers, retained by a short 5/16-24 bolt and nut) are bolted to each arm (five, if I remember correctly); and static plate clearance (typically .060"). I'm using two weights on each arm, which gives me no vehicle movement below 2,000 RPM and no slip above about 3,200 RPM (engine torque is something over 600 lb.ft.).
"... additional applied force by using a lever". Huh? I don't know what "lever" you're referring to. The only "levers" in my CrowerGlide are the weight arms, which are pivoted such that they convert the outward radial force of the weights to axial force to press the pressure plate against the discs. Their lever-ratio is on the order of 1:1. And- "... "in addition" to what?