You know, I am curious as to why anyone would really want to carry a top box. All of my bikes have been purchased used, and each one has had a top-box mounted with a quick release. I take them off and don't put them back until I am ready to sell. It puts weight bloody high, and not only aft of the rear axel/contact patch, the bulk of it is aft of the whole bloody bike. A terrible place to carry weight. So, with fire-retardant suit on, I ask, what is gained?
GL1800A, KLR 650, ATAS, 1972 CT2 Cessna Skylane
Fly low, fly high, but fly!