I had decided to go with the Givi case in the first place. I decided that the bags would be enough. So I bought a Honda backrest. Then I decided I should get the mp3 rack. Then I put a bag on it.
I want to try and keep the expense down by mounting the Givi adaptor to the mp3 rack. In the end I can try to sell the mp3 rack and the backrest to offset the costs.