I'm guessing you have probably got the Powerflex bushes or similar with a more conical tapered top to it, mine is a two part bush there is another flat pad that sits on top held in place by the metal sleeve,

I would of thought it would still only lip over the beam the same amount though.
I have also used this method for removing and fitting the original trailing arm bushes using perfectly sized sockets, and all these methods worked with ease without damaging the fresh powder coat, because I did not trust a garage to do the same.