Toothbrush Holder Cap Replacement (parametric OpenSCAD)

My son wanted to buy this lovely tootbrush holder, but once at home we discovered that the holes were too small for some of our thoothbrushes. So I made this simple cap replacement.

I made it in OpenSCAD so that it can be useful to others just changing some parameters.

UPDATE 2015-07-22:
1. Added image explaining the meaning of the variables;
2. Cleaned .scad file.