The VT 500 will need some rpm to get moving along. However, I lowered my engagement rpm to about 4200 (add grams in heel till it's there, about 5 grams), with heeclickers with a white spring, green yamaha spring in secondary @60 deg I think and about 5 grams in tip on the hc weights. Yes they cost a lot but I never try to save money while clutchng. Just rebuilding the clutches will help alot. However I don't care for the stock shift characteristics, so I went for heelclickers that grab the belt better and hold it, so the rpm rise is not as bad. However the best I've done with this sled is still only 9,5 mpg so far.
9.5 mpg is about as good as i ever got with my sx500r once i geared it correctly with vmaxjhons 500cc clutching set-up. was real snappy corner to corner.