A Simplifying Design

I had planned to cut the tailpiece of the wide angle finder so that it would slide onto the rear of the PVC tube and be held in place by 6-32 screws.  This meant that in addition to a 1/4" long tube into which the coarse eyepiece focuser tube, I needed 1/4" lip about 2.45" ID into which the screws would go.  This meant 1/4" for lip, 1/4" for focuser tube extension and 1/4" at least for wall between.

As I thought more about it, I realized that I could simplify.  Instead of a lip on the outside, I will slide the tailpiece inside the PVC tube.  Thread the holes in the tailpiece and screw through tube into those holes.  This reduces me to 1/2" thick starting workpiece. I could do this with CFC.  But why?  Delrin is not as tensile strong or stiff as CFC, but neither matters in this context.  And Delrin is actually lighter: 1.4 g/cc vs. typically 1.6 g/cc for CFC.