Welcome Steve!
I’m right there with you at 6’5”! I feel like the DX is a great bike for someone my size. Haven‘t had to add bar risers, and the wind issues aren’t really a problem for me Like they have been for several others on here.
As for tires, I HIGHLY recommend the Motoz RallZ tires as they are phenomenal off and on road and they last much longer than a TKC 80.
I haven’t had the problems that you’re having with the shift lever, however, I wonder if switching your foot pegs to something like the new Black Dog pegs would help? They drop the peg height by .05 inches. Might not fix your problem, but I figured it was worth suggesting.