Will,
I understand about the back-pack for storage, what confuses me is that you also want it to be Hi-Viz. No problem with rear visability with a back-pack, but what about the front and sides?
If improving his visability is one of your goals, isn't a Hi-Viz jacket along with a Hi-Viz bp a better combination ?
Just curious here, and since I don't know if he already has a HV jacket, I just thought I'd ask.
Ride safe all, and please, ATGATT.
Greg