need suggestions for 37" spare

[kalantar]

I have a Toyo 37 inch spare on a 20" rim, prior to towing I had a rear rack which I would leave the spare on. I purchased a toy hauler and the spare hits the front jack so I had to remove it. Now I have it sitting in the back area and it takes up way too much space.

I have the option of leaving the rear rack on and removing the spare each time I tow which would be a PIA. I was considering getting a GOBI rack and leaving the spare on the roof but those racks are about 2k and the tire seems quite heavy.

Maybe I can just leave the tire on the roof using the factory roof rack and secure it that way? If I let it sit up there would it get damaged sitting in the sun?

Any thoughts?