I live in Finland so I'm on UTC+2. I feel like allowing rotating might be too good. At least if you could freely do it as much as you wanted. It would take away too much from the actually trying to squeeze in your wanted items (in the early game). Freely rotating would pretty much neglect that whole design aspect. Maybe store could offer some kind of rotating services for a fee or something along those lines.
Do it as a boss reward. Floor 50 boss drops rotate token or something like that. Also, good idea for bosses is to make them have a unique skill. Have like three skills, but as the floors go on, the skill increases in potency. for example, floor 10, 10% more slashing damage. 20, piercing. 30, blunt. 40, fire, 50, ice, 60, thunder. starting on floor 70, increase potency to 20%, or something along those lines. Also, doesn't have to be in that order specifically.