I have a 1990 sidekick with a 3" Calmini lift and the tires are 30x9.5 Mud pro comp

Do I use 15x8 Rims with a 3 1/2" BS or 15x8 Rims with a 3 1/4" BS?

What is the rcomended back space for 15x8 Rim whith my tires and lift?

These guys from a 4x4 shop that installed my Lift ordered me rims that are 15x8 with a 4 1/2" BS and I'm wreking my struts. Later I find out I need less Back space. What is the best for my existing 30X9.5 mud terain tires?

Thanks for any help.
Cheers

The wider rims are not wrecking your struts, they just increase the leverage
over the springs, wider will ride softer, and narrow will be stiffer. either of those
3" something back space rims would be fine.

My preference is a narrower rim, I run an 8" wide rim with 33" 13.5 wide Swampers,
and you could go with a 7" wide rim for your 30" skins

Wild

I guess a 15x8 with a 3 1/4" BS should be good. The Calmini rides a bit ruff. So the wider the rim the softer right.
My tires are like this  \ / in the front a bit ....so this should fix that then as well?

Ya, sort of, you will probably want to get some camber bolts too, but
the wider rims will improve the ride on those Cal Mini springs

Have you had any problems with the camber bolts? Do you use them?

I have a friend and my brother use them, I built my suspension lift
and the custom parts moved the wheel so I don't need them, but
to answer your question, no problems, but you do want to make
sure they are torqued to proper specs so they don't move on you

Wild

My tire shop thought the camber bolts would be too weak since they're "necked down" for the adjustment...so they did what I suggested, slot the holes of the strut, and we used four new heavy duty bolts through it.  Then, in case the bolts wanted to slide in those slotted holes, we added a few small tack welds as added resistance. 
If I ever have to change struts, I just have to chip off the tack welds, or grind them, and then do it all over again. 
I haven't heard much complaints about the camber bolts on here; I just thought this was a better idea.

And, I run the Calmini 3" suspension on a 90 Tracker 2dr, 30x9.50 MT/R's, on a 15x7 3.75"BS rim.  Since half of 7 is 3.5", that means they're "inset" 1/4" from the center of the rim.  I have no rubbing problems on the street and normal trails, and since I got the tires mounted I haven't seen the rocks yet or flexed it out that much.  But no rubbing so far

That sounds like a good Idea... I may do that, Tack welding it would help.

Calmini said for my 30x9.5 Pro comp Mud terains I should run 15x8 rims with at least a 3 1/2" BS or a 3 1/4" BS I think I will go with the 3 1/4" BS because I dont have a bumper or winch yet for the added weight.

Camber bolts are plenty strong, my friend beats the crap out of his rig
and haven't had one problem or failure with them

Wild