Based on your results, there certainly doesn't seem to be much need for an OCAL with the Mewlon,
As there is only the secondary mirror adjustment on the Mewlon, it would appear to be quite sensitive relative to the small change in the before and after OCAL pics.
I notice that there is also very little OCAL ring offset needed, just -1H on pic2. I was needing 6 before then -14 after adjustment on the Newt.
My eyesight has let me down with the TC tool, I'm looking forward to my star tests if the rain stops. 60mm today.
