Take a look at the Mickey Thompson wide rear tires as well as Hoover Tires.

Summit carries both and they have an on-line site.

Even with tread, the wide tires will slip around a bit in the wet, but it's not bad.

You shouldn't have any problems with air leakage due to holes in the side of the rims.
The air seal on a tubeless tire is on the bead.

Since you've got screws in the rim now and the car is going to have a drag racing theme, put the screws back in with the street tires.