Lee,

What you are experiencing is rather common for the make, although the mid range does clean up a little after a few gallons of gas. In the end you'll be able to tune one end or the other really well but if you want a good mid range something else will suffer. Going for the best top end you can have with the leanest safe low end will be about the best that will happen. There have been some that did well in all areas, but a lot have not. Genrally even the rough ones manage to stay running when inverted at mid throttle.