Biggest tire and 15" wheel possible on a 1966 Dart?

Hi! I want to get me some new 15" wheels to replace my stock 14", however I would like to get as wide a tire and wheel as possible without minitubbing, so now to the questions

- What's the maximum possible tire diameter

- How wide can I go and still keep within the fenders?

- What's the maximum backspacing possible on the wheel?

- Anything else relevant? For example I assume that a 295/60 -15 on a 8" wide wheel would be impossible? Well just try to answer as best you can =)

Best regards!