I made and used this on one tour with a large Givi monokey top box. It worked just fine. Don't need it anymore. Just remove the cowel or seat, click this into place, mount your Givi or Kappa top box and go. Simples. The seat is a genuine Honda seat ,not some cheap copy and the plate is a genuine Givi or Kappa Monokey Plate. £55 inc P+P UK mainland.
It sits in the same place as the cowel obviously so the box is over the cowel area, the front of the box is just a bit forward of the plate. You probably won't touch the box unless you sit right back in the seat or if you're horizontally challenged. The box (well my box which was a 46L box) sits approx level or a tad forward with where the front of the cowel plate is now. I'd mount it and show a photo but don't have the Blade anymore which is why I'm selling it.