Thanks Wayne!
I felt invincible and immortal in my 20s. In my 40tieth year I know I am very much mortal and subject to stresses of all kinds.
Guy who taught me mountaineering/climbing was in his 70s back then. 20 years later he is telling me that he is beginning to feel the age. Still active in off-piste skiing, climbing and ocean swimming through his 80s. Similar quotes from others with more experience who still are motivated and active give me hope Avoiding flab and retaining max strength seems to be the key?

Snowbiking!! Now why is that more fun than skiing or snowboarding?? I mostly go backcountry with my snowboard and I have a problem seeing myself enjoy the ride down again on a snowbike

A-cat sail area incl mast is ~13.94m2 with 0.1m2 of board area in total?
Higher AR should increase efficiency but some area is still needed. Would be very interesting to have some numbers on this.