I think I had a 70 jet in there after the pipe, a 68 before..but dont quote me on that. I know it was at least in the 60's. I'd try something bigger than the 50's size. Maybe a 60 especially if you ran it and it came out a little tan, you want a little darker so go up by 2 jet sizes.
You should be able to watch the variator as you climb a hill, it should change in size depending on the hill. The front variator gets smaller when climbing hills and bigger when you rapp out up top on a flat surface, if you hit a hill and the variator doesnt go back to a smaller size, it might be getting stuck open.