A luxury problem but nevertheless an interesting topic.
I think that if you're not using the mast in another sail, why not let it develop a "set" for the specific sail.
I see no harm in that.
As long as the rig keeps out of the full sunlight.
I've already had a 490 mast snap in a rigged sail laying for more than one hour in full sunlight on the beach.
When I took out the mast, I was very surprised of the "almost boiling" temperatures that came out of it
Probably the bigger rigs will have more problems with it.
IS87 / IS101 / RRD114 / US147