Doug,
Yes they are a different shape to Bob's, but are the same size and depth.
I rest my tube on these knobs when transporting, or moving around at home.
Unless you twist and turn the tube whilst on the ground (unlikely) the collimation will not be affected.
If you have the stronger springs, you can kiss the locking pins goodbye.
I've made these changes to my Lightbridge and the difference between original and modified is "lightyears better"
