Just throw the primary gear on and be done with. Then throw the clutch together and call it a job done.

The primary drive gear is not balanced and does very little. I skimmed mine down on the 300 a considerable amount and just bolted it on. Smooth as silk.

The primary driven gear is balanced at the factory, independant of crank etc.

The clutch basket is just a cast lump, so there would be some benefit to bolting that onto the primary driven gear and balancing the assembly.

If your NSR is full of vibe, then I suspect that the crank is out of true.