Brian,
I found as much of the problem in the spongy nature of the rubber on the sliding foot hence the longer base I made.
I will take some close ups of the mount and test pics using Robs bar code tests. Trouble is this lens has turned into a cloud magnate.
I have managed to sneak a moon shot in the dark but have never managed more than 2 shots before the cloud mysteriously appears.
A bean bag would certainly help as Roy has suggested but that does require the lens to be at less than 45 deg. I did a test with a bag of sunflower kernals and another with a sheet of lead ( same thing but not so handling friendly ) and it did absorb vibrations.
Don