Still playing around with my Homed Brewed Luggage Rack. Spent a hour at a friends shop and used his engine lathe to turn the support spools for the rack. Had a piece to 7/8" aluminum round stock which I drilled and parted to size. The offset in height between the front and rear backrest mounting holes is 5/8". Made two spools 1 1/8" long for the front and two 1 3/4" long for the rear. Those lengths put the rack on a even plane. Im going to paint the spools satin black which will closely match the backrest bracket.
Finally finished my rack. Took some time getting the proper material but the wait was worth it. The original was made from a cutting board and had silver fleck and was smaller than I wanted. The new material is solid black and the blank was 12" x 18" which allowed for a larger rack. The material is commercial 7/16" black vinyl which is both durable and weather resistant. Used my hand saw, drill press with 3/4" and 1" spades bits to shape and drill the material. A simple task IMHO.
Bob - good looking platform. I did a similar board ; but mounted it on top of the small factory rack. By the way , I stood on the factory rack with all my 190 lbs. ;it didn't even try to break. I had to know before we left on our road trip. We strapped at least 30 lbs. on it for 3976 miles.