I have a Givi Monolock B47NTML Blade Tech top box from my old scooter that I wanted to mount on the Swing but didn't want to pop for the cost of the Swing specific mount. After looking over the universal mount that is included with monolock boxes I decided to see if I could get it to work.
The only mod I did to the mount was to cut away a little plastic in the center so it would sit closer to the front of the spoiler. In hindsight I'm not sure yet if this was a good idea as it now sits close enough to the pillion to be a back rest. Just have to wait and see if that will be uncomfortable for my rider leaning against the case without a pad. In any case I'm sure something can be rigged up to give a little padding if needed.
I only used 3 screws to hold the mount on the spoiler. I just drilled holes where the two rear outside lugs are molded into the spoiler for the rear screws. I then eyeballed the front center screw to a place that I thought would be as far forward as I could go. I may change the front screw to a shorter one as the length does tend to bow the bottom cover of the spoiler a bit. You can see the pic for the bolt locations.
Overall an easy install and it is very sturdy. Just hope this helps someone else if they are trying to decide to use the universal mount of buy the custom Givi mount.