Nicolas, I was just rereading your post and admiring the photos again, and I noticed you mention the difficulty in winding the jumbo. Mine was made some years after yours, to be sure, but the movement should be the same. I agree that winding the watch is hard on the hands, but I have also found with mine that the rotor efficiency is such that if I even merely pick the watch up, the movement begins ticking. After I have left it for a while and the PR is fully depleted, I usually just give the crown but a few turns, set the time and strap it on. It then keeps remarkably, and I mean remarkably accurate time.
I don't want you to risk hurting your fingers. You have a lot of watches to keep ticking. ;-)
Best,
respo