Rims & Backspacing

Any insight would be helpful and please correct me if I am wrong on anything.:
2006 TJ with a Barns over the knuckle Y-link set up. So, I want to get an inspection. Apparently, I can’t run stock TJ wheels at a 5.5” backspace because they rub steering on inside of the rim. Do not ask how I know this. The 15” rims with 35” tires that came with the jeep have 3.75” BS and just clear. My 15” rims are 3.5” BS and obviously clear even better. Same goodyear 35” MTR tires on both existing & my rims.

Backstory, this is Jamie’s old Red TJ. We want able to drive it on the road but will wheel the hell out of it as well. These stock tire will probably see a few road miles maybe even a few drives to F & F where we swap out for the stickies !!!
So, questions:

I currently have 15” rims with 5.5” BS. Should I buy 1.50” spacers or 1.75” spacers ?? 4” of BS may not be enough. But 3.75” should be.
How much spacer is too much ?? Will only be used for on road driving.

If I’m buying spacers anyway should I buy 4.5 to 5.5 adapter/spacers to get stock (JK ??) 17” rims ??Now a 17” rim from what hear 6.25”. The rim is 2” wider in diameter would 4.50” to 4.75” of BS clear the over the knuckle steering. The 17” rims seem to be all over FB marketplace really cheap with better tires. Plus, the 17’s would look better when on.

Last question If running 1.50" or 1.75” spacers with the stock TJ rim with 5.5” BS is a viable option does anybody have one stock TJ/XJ rim with 5.5" BS.

I have 16 inch rims on my jeep. We can swap tires for your inspection and then switch back

Just an FYI. JK wheel pattern is 5x5, not 5x5.5

Yep got confused with all the bolt pattern & BS talk.

17s are the new 15s. There is much larger tire and wheel choice for 17s. Get 17s with 4" backspacing.

Think that comes stock on any jeep. I was looking for a cheap set of stockish rims & tires for inspection. All the 17’s is see are like 6.25" BS Once inspected I will run the 15’s with 3.75 BS that came with it.