Good luck with that leak down
I don't think you can get a PV engine to hold, at least not without lots of work. The trans vents through the PV so anything coming out vent tube, is it just what's leaking past PV or is it a case leak, crank seal? If you have comeplete clutch cover off at least check crank seal with soapy water.
89 rm I recently did , I was satisfied with small leak on PV cover screw, which you can't get at with eng/cyl in bike.
AS to clutch, file the basket. Even if you don't get grooves 100%, still better than what it is. Make sure plates don't index like Blasters and PP is corect. Don't forget washer.
Sometimes an engine/set-up will have a "spot" that seems like no matter what you can't eliminate. It could be due to aftermarket pipe, or just engine design, Quadzilla is good example. Without lots of testing/parts such as different cutaway slides, needles, emulsion tubes, you may just have to live with it.