Wheel offset/backspacing american racing 172 bajas

Need some help.

What offset/backspacing do you think I will need to clear the uca with a 2" lift.
Bilstein 5100 set to 0 with ome884. Jba uca.

Originally I had them preloaded to .85 (lowest notch on the 5100s) and it didn't rub the uca, just the cab mount.

I lowered them down to 0 last night, now I rub the uca full crank reverse/forward sometimes. I have stock 17" trd sport rims with 1.25" spacer.

I rather not raise the shocksback up because the difference is night and day to me with having them just slightly preloaded.

A fellow members suggested removing the spacer to prevent it hitting the cab mount, I did that, it helped, but now it rubs the uca.
I am planning to get rims soon, I am probably going to exchange the 17s ko2s and switch to 16s.
American racing 172 baja with 285 ko2s.

Will a 4.5" backspacing with 0° offset give enough clearance to not rub the uca or should I get a -12 offset?

Ultimately i wanted try everything before i do the cmc, but now I rather do the cmc than have the tire rub the uca.

This issue is bugging the hell out of me and I just want to get it done haha

 

On Jba’s website it has the wheel specs with tire size to clear the uca.

 

I had some outlaw ii’s in 16x8 0 offset that I had some 285s on and it cleared my spc ucas but not by much. I never rubbed the ucas just the cab mount.

 

285s on an 8" wheel with a 4.25"bs will work fine. As for minimizing the chance for a cmc, get an alignment with increase caster when you get your new wheel/tire setup.