I have purchased a set of Rivco mirrors but didn't like the adaptors that came wit it, so this is how I fitted mine (on a 2005 Rocket)
First: Find a bit of Stainless Steel and make new adaptors, where the bottom part of it is a copy of the old mirrors, using the old M6 bolt and springwasher.
The adaptors is almost done. I have made the thicker part 24mm long which makes the base of the mirror sitting 18mm above the bracket.
Using the 5/16" bolts that came with the mirrors: Work out hos much thread is needed to screw it in tight in both parts (mirror and adaptor piece)
Screw the adaptor on the mirror and it is ready to be fitted to the bike.
The spacers are lifting the mirrors to make more space for the leads. No pinching.