I'm on JBA High caster standard UCA's and I can tell you that for tire clearance they are worse than the factory arms because of the way they sweep out towards the joint to give you more pre-built caster.
I am on a 315 tire (35's) and my factory arm did not rub with my 17x9 -12et tire, soon as I installed the JBA's I noticed rubbing start at near full lock. I am on the Bilstein 5100/OME 3" suspension lift and 1" body lift.
With my setup, I estimate 1/2" spacer would have done the job, but since you can't run such a thin spacer without custom machining I just had 1" spacers delivered. Down the road I plan on getting a 9" wide wheel with something like a -20 to -30 offset to not have to run spacers.
With that said though, is this a new lift you just put on? New tires? a little more information would help. Do you have the body mounts chopped? It should be fairly easy to see what is rubbing.. just turn to full lock and get under the car and see what's going on.