I had the same exact experience on a Gila with an 8p, tomos cdi with parmakit box, vforce reeds, oko 24, new lightened bell from treats etc.
it was horrible with the stock springs, i tried the lightest ones first as well. the way the clutch would break free and rev out to max RPM with any sort throttle position over 1/2 throttle was horrible, especially while trying to break in a new clutch bell and not glaze the pads and ruin the clutch. I was using royal purple max atf for this.
I tried the malossi white springs and it was a whole new clutch. Actually engaged smoothly and evenly, never would break free and rev to max RPM.
tldr; the springs the clutch comes with are terrible, absolutely useless on the bike I was tuning. the malossi springs make this clutch usable, and I only tried the white ones.
the jammer 6.4 clutch should not be sold without the malossi springs imo.
i'd like to mess with one more on a little bit tamer setup but i don't think i'll be building anything any time soon. or maybe not who really knows? (edited)