Yea that bolt is a test of patience. You cannot attack it you have to feel your way and get the right spot to get up in there. I jiggle it to make sure it starts going back in. A little anti-seize helps. I also chased the threads on the bolt and the weld nut in the frame.
Did you try squeezing the bracket top and bottom some on the back side where the gap is?
I'm not sure a new bracket will help, just some adjusting of the one you have. I was persistent with mine and tried several methods before telling everyone about these. If you keep at it, it can work with just the sleeve. If you cannot get it tight then I guess try the thin rubber gasket stuff but make sure it gets tight, you will have to check for wear.
I tried a piece I sliced off some of the 3 inch ones I shortened but the diameter being the same will not slide over it. I cut the ends off of it and tapered it to conform better. Being spring steel I can compress it on there flush in the vice. I left enough gap that I hope it will squeeze on tight when the bracket compresses it.
If that somehow works, for those of you that cannot get it tight, I can just give you one of those pieces. I'm glad I'm a hoarder!
In your case if you don't want to try to adjust the bracket see if this will go in there and tighten up and report back.
PM me your address. I want to help you get this right. It won't conform as far around in contact with the bracket as the sleeve alone but if you get the bolts tight this might work for you.
I have 5 extra racks and the one installed. They are all the same diameter and so are the brackets.
However as noted somewhere way back there the bracket is not shaped exactly round rather it is horseshoe shaped to conform to the OEM rubber bushing, we know how well that worked.