Well, problem is now solved. First, along with the extra effort from the stiffer springs, shifting got much harder too, as if there was excessive friction in the clutch even with the lever pulled in (and yes, I checked the adjustments).
Here is what I did:
1) pulled it all apart again
2) did some light filing along the edges of the hub and basket to smooth out the gouges a bit. They weren't bad, but this filing can't be a bad thing
3) bought a zx10 clutch cushion at the local kawasaki dealer, installed it as the first steel in place of the suzuki rings
4) assembled it up...since the kaw cushion is thicker than the suzuki steel, it was too tall. so I removed one fiber from the middle of the stack. now goes fiber-cushion-fiber-steel-f-s-f-s-f-s-s-f-s-f-s-f-s-f. Since the steels dont slip relative to each other, I figure this would be OK, and keep me right about at specified stackup height.
5) used the stock springs
6) filled it up with non-synthetic oil
And it all works great. No judder, grab, bark. Great, smooth controllable engagement no matter how I do it. And the shift effort is back to what it should be.
Thanks for all the advice!
1K4: k&n a/f, ivan's tre, PC3, micron high mt, -1+2 driven, spiegler SS, galfer hh fr., ebc hh r., frame/swingarm sliders, speedohealer, pwr pures, hotbodies undertail-custom signals