The short version is the common one used.
Handles interfere I would assume.
You need the Honda oem saddlebag brackets and a piece of flat steel to bolt between the bracket and the backrest (and to entend the bolt holes out wide enough for the backrest to mount up to.
Disclaimer: I don't have this setup but studied it heavily because I was planning on doing it.
HValkrider - Thanks for that extremely valuable information!! Such an obvious solution, but I've had my mind going to the most complicated places for weeks upon weeks (mainly because of the curves in the rear fender). Occam's Razor prevails again!
I have a couple questions if you don't mind. First, what made you decide not to do it? Second, it looks to me that the piece of flat steel used to extend the saddlebag bracket could or should have been cut out at the bottom to match the bottom shape of the Yamaha bracket. I can see a screw into that piece of steel that appears in an asymmetrical place. Doesn't look quite right - maybe that's where the flat steel had to be screwed to the saddlebag bracket to avoid having to put a curve in the flat steel piece??
I found the saddlebag brackets for only $96, but I'm still conflicted. I'd rather not lose the grab rails. My goal here is not so much the passenger backrest, but to have a sissy bar and rack to put a small bag on. I want to keep the Valkyrie as clean as possible, but you do need to have some stuff with you unless your just cruising the boulevard.
I have one more possible solution before I go to the Stryker backrest. I wrecked my VTX1800N back on May 30 (3 broken ribs are a bitch). I was able to salvage some stuff including the backrest which I really liked. It's the backrest with the wide nicely curved chrome uprights that narrowed down as they went up. I think I can adapt it to attach to the Valk's grap rails. I'm going to have to put some curves in the uprights to narrow the width at the pad connection. If I can get this right, I'm going to remove the chrome and have it powdered coated to match the Valk's silver grab rails.
Anyway, thanks again for the info!