What solution(s) are available so I can pick the axle height with relocation brackets? What I'm concerned about is if the brackets are pre-drilled but the holes still put the axle too high or too low. I'm looking for something the functional equivalent of a slider or a vertical double-ended heim joint which can adjust the axle height instead of pre-drilld holes. I can drill more holes, but will be concerned about integrity of the bracket.
Jim....aren't you asking this on the wrong board???
If you were to do anything like that, I'd use a serrated mounting "slider" setup (think dirt track/oval track PHB setups). With the loads on that joint, I'm afraid it might not stay where you put it. I'd probably do as Rob and Jon did and drill the holes you need (you may need to weld on a doubler on the outside to give a place to put the holes).