I keep the microscope base attached to the scope at all times and I put the lens of the scope right on the edge of the knife. It doesn’t effect the pictures on the WEPS, but the loose base did swing a bit, making it more cumbersome to control the scope sometimes. The tighteneing of the screw for me will help tremendously when the knife is not clamped, particularly when I do my straight razor progressions.
One drawback of putting the scope right up on the edge is that you can easily chip the edge, especially as you get higher in grits.
I’ll post a picture – tonight I will try to get to more of the progression.