I just use the soft side of velcro and stick it to the side touching the wind shield.
Heck I use velcro to fix everything is the duct tape of the y2k

 

Hey...theres an idea!...I can sell the two left overs as custom HD parts on EBay!

<insert ROFLMAO smiley here>

 

I fixed my triple bag from rattling.

1st : I pinched the tabs that hook to the inner faring enough so that they were tight and didn't have any when I slid them on.

2nd : I put larger rubber feet under the bracket to sit on top of the inner faring. 1 foot in the middle and 1 under the opening between the outer and center bags.

3rd : I put small squares of velcro on the back corners of each bag and on the windshield. You don't notice the velcro but it keeps the bags connected to the windshield so it doesn't vibrate.

 

I have this exact bag, I cut out the metal mounting tab, had to drill out rivets, wropped the bottom and back with the felt half of a velcro strip, had to JB weld the felt strip to the bag to secure. Just attached the velcro strip to the faring. No excessive movement and can ****** off in a minute for washing of the bilke. Also put a velcro strip on top for speed pass and remote for radio.