Customizable Center Dot Creator

EDIT: There's now a 3 prong one which should work a lot better with any scope like this. As well as the 4 prong one.

This is a tool for creating custom guides for center dotting telescope mirrors to aid in collimation.

I think it will work with Thingiverse's customizer.

You'll need to know the diameter of the mirror, and the diameter of the center dot you will use.

Then you will need to generate the locator, which is the thing showing the location of the center dot. Optionally, you'll then want to generate what I called the placer, which is a simple cylinder you can put the center dot on, and use to align it. (OpenSCAD values locator and placer =1(on)/0(off))

Important values:
mirror_diameter (in mm), center_dot_diameter (in mm), center_dot_hole_diameter (in mm)

Additional features: (Inspired by this: https://www.thingiverse.com/thing:2556543) You can have, it generate cutouts to save material with arm_cutout (mm of cut length, currently 1/2 of the width. (It do