The only thing I've noticed using a 85 from an 89 is that the fps increased so in theory I got better efficiency. I normally shoot 3* so very rarely get problems anyway
I've used good paint and it's been ball on ball. No matter what barrel I use. Also used cheap 5hit paint bore matched (best I could) and couldn't hit back end of a bus from ten foot away. Imo best getting the better paint everytime.
So barrel for efficiency and paint for accuracy. Its a pain in the butt because most walk ons you have to buy there paint which is usually crap from my experience...