1959 Rambler Super Sedan Tire Size and Gas Tank Needed?

I just spent hours trying to find tire size and gas tanks to no avail so here I am...HELP! :-)
I have a 1959 Rambler Super Sedan (with fins). It has 205/75/r15 tires on the back and 195/75/r15 on the front. I'd like to know what the "original" tire size was so I can use a vintage tire conversion chart to see what moderns size tire I'd need.

If you have a 59/60 Rambler Super (4-door) please let me know what size is on your car.

I'm also searching for places where I could buy a fuel tank or gas tank for this Rambler AMC car. I'm not keeping the car original so plastic tank would be fine. I haven't looked at the condition of the tank straps yet but any info on replacing would be greatly appreciated.

This car is very light weight and I should get some excellent gas mileage! Regular gas works just fine for these old cars.

Thanks ahead of time!