I've played a few accordions over the years that have definitely become sluggish when played in an outdoor humid environment, but that wasn't anything to do with reeds and everything to do with fingerboard construction and wood swelling issues.
I guess you build enough, you work out the little things, and it's always the little things.....
One thing I know he changed over the years is he makes his rockers wider (3/8" as opposed to the normal 5/16"), this allows him to leave more slop in the rocker slot. The wider rocker has more surface contact with the axle so that negates the slot slop, at least I think that's why he did it. Then you only have to worry about the axle hole seizing the axle, which sometimes happens, but that seems less finicky to prevent.
The biggest issue for me has been the button hole. That is also prone to wood movement causing the button to catch on the back of the hole. So I started slightly elongating the hole, but if not precise, it allows the finger to get pinched sometimes. This accordion building thing has all sorts of little issues like that, and many of them are caused by the instability of wood.