I went a bit overboard, and I doubt much good was done.
Without a picture, this is going to be hard to explain, but:
I bought a "turnbuckle" from a local hardware store and fastened a wide and fairly deep "L" bracket at each end using lockwashers and nuts. By rotating the center of the turnbuckle, the two L brackets spread to each side and pushed the steel U-Bracket housings for the urethane bushings outward against the mount shoulders.
I actually think I took that idea for that tool from George on this site who made one and posted a picture. I'll post one if you are the least bit interested. By eyeballing the compression and gaps I really don't think I got them all that tight.
The tool resembles the one in the Shop Manual. It can only be used on your back, under the car and with the flat of each L bracket resting on the rack/tube and pressing against the steel U-Brackets.
I made the tool in an hour. Turnbuckle, threaded rod, a couple of drill holes and two pieces of angle iron. As I recall, this will not work if the bottom of the L on the angle iron isn't deep enough to avoid the upper part first contacting one of the frame members.