radman
R.I.P. Our Motorcycling Friend
Drill from the outside, bag mounted and firmly in place. Use 3/8" bit, and 5/16"pins. This is how I did it a year and a half ago. A little angle is fine. Center on the rubber pad mount, and have at it-easy to do, and the slightly smaller diameter pin makes for easy install/removal.Don't know the dril size, but I remember he said he drilled from the inside with the rear tire removed. Get the pins and use as a guide for bit size selection.