I've been down the same road with my 315.
I now have CR250 plates in it and I use ATF.
This seems to have improved the drag substantially (once warm), but I'm now struggling with the lack of "gradual-ness" for want of a better word. My clutch is now more of an on/off switch. Nothing happens in the first 70% of the clutch lever movement, then it's on/off at about 75%.
Any advice on what could be changed, fixed, adjusted to give a more gradual engage/dis-engage ?