A centering pin should do the job. But, it looks like Rebelwork's plate is threaded for a conventional bushing size. I found a set with the quarter inch bushing somewhere a long time ago. Nice to have the shorter tube on the bushing.
I don't use the PorterCable type jig for dovetails. So I just use the bearing on the bit to ride on the comb of my Katy jig. Same with the Incra as well. I watched an accomplished woodworker spend an hour on a demo of the PC type and never get a joint that fit. Much easier on the type where you move the wood over a fixed router than the other way around.