I ended up hard mounting these to my v-star 650 classic . The throw over part just didn't secure properly. Removed the inside flap and clips by cutting the threads, then drilled using a 7/16 bit a hole about 3" from the front and right where the threads were holding on the flap and clips, then 8 1/2" down drilled a second hole.
The bags are sturdy enough to hard mount, used two large washers (one on the inside and one on the outside and a rubber bushing against the washer and Chrome on the bike. Then tightened down the allen head bolts and attach the rear tie to the tail light frame. For the 650 classic, i didn't need saddle support, but for other bikes you may want to consider if the sides are not rigid enough for you.
These will allow you to mount and have a passenger. However the bags will be right up against your tail lights. If you move the bags up front more, your passenger won't be comfortable as the bags will make sitting a bit awkward.
Just get the XXL instead of the XXXL like I did, but I wanted the big bags as I carry alot with me to work.