This view shows the difference between two mounting methods. A solid 6061 aluminium block should provide very rigid mounting but yet simple enough.
I made these by using hand drill and hand saw, persistence and patience is the key. It's now much lighter than the setup which I got from the original owner, and it even provides slow motion control which is absent previously.
I've tried to test this setup out in the same afternoon by using the sun as the target. Unfortunately, there was so much cloud around, but fortunately, I could truly test the tracking capability of the mount under this situation since when there was a short cloud gap, I could always see the sun!