And we're ready to rock and roll. I got a length of soft braid (they had shinier stuff but mine seems to be made of something cottony) to act as the shoulder strap.
I had to figure out how to insert it between the zippered top and the body of the bag so that it would end up on the outside where it belonged but that wasn't too difficult. Here I've pinned the zippered top to the bag and the shoulder strap is inside the bag about 2 inches so I can sew it down for extra strength.
The handlebar itself is packed so I used a lamp to simulate the bar. It doesn't show very well here but my plan is to loop the whole strap over the handlebar and then snap the loops onto the bar as well, creating a redundancy. This bag will contain all the little things we want to keep handy while riding (like the camera and money) so I don't want it to fall off.
I figured that I could use an 8 inch loop over the handlebar on each side so that's where I placed the hammer-on snaps. Here is the bag hanging up, with the loops snapped shut. I'm pretty pleased with it even if I won't get to test it in action until we get to Halifax. I've put a few notes on the photo if you want to go see them at Flickr - nothing exciting.