I'm currently running 14/46 and it's working well for me. Within an hour from my driveway are a variety of terrain options; single/double track, FSR, graded roads, gravel and open desert. I can hold 75mph at around 6k and topped out at 104 (speedo indicated) on the dry lake bed at El Mirage while 1st/2nd are better for technical stuff than when the bike was delivered.
As far as your advanced setting going flat at the higher rpm's, have you replaced the stock exhaust yet? My choice ended up being the header and slip-on from FMF and after a 15min idle reset, the bike pulls to the redline in 6th with no problem and no noticeable dip in power.
One added note, when I swapped the counter shaft sprocket to the 14, I went with a regular sprocket vs the rubberized version and the chain lash/noise is noticable. I'll be ordering a 14 with the rubber cushioning with my next parts purchase.