If you want to pair the Pro-Tac Driver Backrest up with a pair of Leatherlyke Saddlebags, there is normally an issue with the thickness of the PT mounting lug interfering with proper mounting of the LL bags.

The simplest, and strongest solution to this issue is to use a set of Suzuki rigid saddlebag supports behind the LL bags. These supports will not only add the necessary spacing to the bags, but will support the bags at the proper angle, add considerable weight carrying capacity to the bags, and prevent the bags from flopping around on the bumpy stuff.

Of course, you will have to purchase appropriately longer bolts, but these are readily available at most hardware stores, and the use of these supports means that when you pop off the bags, you will still have the supports on the bike.

A couple of years ago, I made some modifications to my Leatherlykes so that they would fit around the Pro-Tac mounting lugs. This works, and allows the bags to fit in close to the bike, but it does weaken the integrity of the bag material at a crucial point, necessitating the use of additional supports for the bags.

If you're interested in drilling and grinding on your LL bags, click the link below for details on what I did.
Leatherlyke Modifications.

SNAKE MAIL