Took me a while to get this just right.
I used a combination of Windows 10 3D Builder and Blender.
The holes down the sides will fit a 28ga wire in each one.
You might have to use a 1/16th drill bit to drill out and clean the holes. Not difficult.
Monoprice Maker Select 3D Printer v2
Sliced in Simplify3D
Auto Generate 2.00mm Support Pillars for Max overhang of 45 degrees is plenty.
Adjust as you see fit.
Mirrored, Measured, Merged and Tweaked using 3D Builder
Cleaned up the Vertices and Faces in Blender