Cragars and sizes

Another question to ask , are the rear wheel openings the same between a Notchback and a Fastback. I don't know that answer for sure.
14 or 15x6 will work all around depending on tire size of course. 7" wide may work on the front and should work on the rear. Lookimg for a skinny/fatty 60s look? 8" wides "may work" on the rear. The wheel manufacturers usually have around a 4" backspace which works with most applications. Anything more than 4 1/2" backspace and you run into inside tire rubbing issues in the springs.
Yes, Cragar still makes them Summit has them listed. Here's a link to all the 5x4" bolt circle wheels they handle. The Cragar SS's are in there. Wheels Wheels Wheels & Tires - 5 x 4 in. Wheel Bolt Pattern (application) Parts & Accessories | Summit Racing