Forgot to add that I am new to the forum and this is my first post 
I have also installed Viking on my motorcycle and my friend helps me with installation, for make it removable you can install their quick disconnect.Then used a nut on the backside as a jam nut. Only issue is that in order to remove the bags, I have to remove the whole backrest assembly. However, that is a rare occurrence.
I looked at doing that, but the reality of it for me is that I generally don't remove my bags. These are locking, and I have the lock tab removed off of the left bag, as I use it for quick access to and from work. On longer trips, I reinstall the lock tab and lock them down. I have found that once you get used to having the bags, it is hard to go back to not having them and wearing a back pack...I have also installed Viking on my motorcycle and my friend helps me with installation, for make it removable you can install their quick disconnect.
I ended up buying a Cobra backrest & sissybar combo with rack so I could mount them. I still had to mount the forward mount at an angle to clear the shock cutout. Filing the toss-over strap in case I have any problems with the FAT brackets. FYI - I did have them send me the other set of mounting brackets and it was the same problem.
The kit that they sent to install them as "toss-over" had instructions that instruct you to drill holes in your bags and attach them to your bags, their bags are nice but their instructions really suck. If you do decide to do the "toss-over" you will still need a bracket behind the bags to keep them in place, per the original instruction, and there is a strap on the bottom of the bags to secure the bags to the brackets. View attachment 241258
This is what's in the hardwarekit, you'll still need the bolts from the original installation kit
View attachment 241259
This is the hardware kit that you can request from Viking
View attachment 241260 View attachment 241261
This is installed with the FAT bracket.
Good luck,