It sounds like you might be better off gong with a 270 needle jet and keeping the jet needle on the 2nd clip. If you do stay on the third clip you might be able to go back down to the 266's.
The mains are often better off leaner than stock. They jet them rich to be on the safe side. They jet them lean at idle and cruise for the EPA.
A huge factor in all this is the airbox top. I highly recommend trying the R80 one large/one small airbox horns versus the two large and remember that to give both setups an equal chance you might have to rejet for both setups. They make a BIG diff.