I finally ordered and got the helper bags installed in the rear of the Burb.
I also realized that the bracket on the axle for the panhard bar was hitting the crossmember above it when I would hit a dip in the road.
I knew something was hitting but assumed it was bottoming out the axle bumpstops on the frame.
So I trimmed the bracket
and notched the crossmember for clearance.
And installed the helper bags.
I ran the bags separately instead of using the T fitting and hid the Schrader valves next to the filler neck.
No more bumping and banging over dips.