Will it fit thread

Yup, that's how it works. The less backspace the more the wheel will stick out. But if you overdo it you'll either end up with a lot more rubber outside the quarter, or a skinnier tire. I think 4.5" is the most you'll want to run, I'd say the least is probably around 4". More than that and you're not benefitting from the clearance to the spring.
That’s what I am looking for, thank you. Your wealth of knowledge on this subject is invaluable, I appreciate your input.