I suggest that when the WOF gives a booster as a gift it should be added to the boosters already owned by the player - in the way that bought boosters are added - without having to pay for storage.
The situation now is that if the player wins a wheel booster and the three spaces are taken, the player has to pay to store it. I believe this is a slight improvement over what used to happen. IIRC, the boosters used to just disappear if storage was full. However, I dont believe this payment for storage happens for any other wheel gift. Extra barn stores are added to the barn even if they take it over the barn limit.
I would like the wheel boosters to act the same way. As I said above, boosters work this way when we buy booster packages so the code already exists.