To follow up on my thoughts on using the Mustang pads with the Ultimate seats: I spoke to Mustang today. The 12 X 9 Passenger backrest pad can be special ordered without sissy bar specific mounting holes. That would work to be able to mount them on the Ultimate backrest brackets in place of the Ultimate pads However, the rider backrest pad with Mustang has it's brackets mounted directly into the pad and can't be separated. So the pad alone can't be used as a bolt on.

So, at this point, the only option to use the Mustang backrest pads would be to use their 12 X 9 inch passenger pad for both rider and passenger. That might be possible or a 12 X 9 may be a little too big for the rider.

Looks like I'll order the Ultimate King with both backrests. I can take my Mustang pad off of my VTX and hold it in place on the F6B with the Ultimate seat and see how it would look. It may still work. For now, it's just a regular 3 piece Ultimate set. I'll keep you posted and take pics if the Mustang/Ultimate combo works out.