just pop the inner frame off the fender.
If I remember its just the 3 front bolts, and two Torx heads holding it all together,
(after you remove the fender bolts).
bend the wire holders open and you got lots of room to work then.
To answer the question,
Yes I've relocated my tag, and I'm fixing to weld on the inner frame some,
and relocate it again.
My tail light has leds for the tag light, so that may not help you,
but since I got a new tail light,
That I now have to modify the inner for yet again,
I'd sell my old one. (the one I'm currently using)
No wait, that wouldn't work for you either, its a chrome cats eye with built in turn signals that fits my bobbed fender.
Sorry. But the first part of this post should help you out on part of the problem.
Good luck,
skip