Hi,
Below are the listings for new fan hub gaskets at TM Tractor Parts, if you can enlarge the pictures, maybe you can guess at the thickness of the gasket material you would need to make them.
It looks like they are not thick, but not thin either. https://www.tmtractor.com/new/co/755fp.htm
I’ve heard it said on here that there is only one gasket on the Cub whose thickness is critical, and that is the engine oil pump gasket. I would think whatever gasket material you have on hand would work for the fan.