I am also 63 and, and can say that the GS is the most comfortable bike I have owned, not just ergonomically, but also in terms of allowing an unstressed riding experience, which is at least partly due to suspension, handling and power delivery characteristics, plus I went for the lowered chassis version which allows me to easily flat foot while using a standard height seat in the high position to minimise leg bend. However, even with the GS I have had to make some mods, namely a larger screen, the more comfortable BMW Exclusive seats, plus bar risers. The latter are a recent addition, and have made an unexpectedly big difference to comfort.
It is also not simply a question of your height, as seated height can vary between people of the same overall height. In my case, although I am 6' 1" I have only average legs and a long torso, hence when sitting I found I had to lean a little to reach down to the bars and it turned out that this was just the wrong angle to aggravate an old back problem. I fitted the up and back risers and it has transformed the situation to the point that after a recent 400 mile ride I had not a twinge, and felt like I could easily have gone much further.
Sounds like a nice long GS test ride is in order!
Fred
