Buell,
I'm 6'4" and flat foot my WR w/tall Guts foam when on level ground. I sat on Ret Seniors bike and my knees were higher than my hips - I don't think I could do the sitting/standing transition more than a couple of times w/o hurting myself. I also run Thumper Racing +1.5 inch forward & up bar risers so I can actualy stand comfortably on the bike.