After missing a chance a couple of years ago I finally signed on with Scoot-Tours. This should give me more information on modifications. GiVi said to wait 2 to 3 weeks for the catalogue. Avery Frail took some great photos of his backrest installation. They are linked below.
First impressions are positive.
The ample fore and aft adjustment allow you to sit up 'real close' or lounge back. It means you don't have to hang on anymore. All photos are by Avery Frail and are used with his permission. Rich has some great items. I recommend that everyone who is going to customize their Helix look at his options.