Customiser: Thumbwheel with scale (Remix)

This is a first go at a customiser for http://www.thingiverse.com/thing:874155 by jamesarm97, which was derived from http://www.thingiverse.com/thing:844008 by positioning the nut underneath, which in turn is a descendant of http://www.thingiverse.com/thing:225188, by adding knurling.
Variable names remained mostly unchanged, so did their initial values. At this point I only wanted the scad file to load and render, using the customiser. I'm sorry if some parameters don't make huge amount of sense now, as some seem to partain to one of the originating versions. I'll go through the file again and try cleaning naming, values and descriptions up a bit.
Making this design suited for the customiser should address the frequently stated problem of not well fitting nuts, possibly expressed by people who don't have OpenSCAD, and are therefore unable to change the relevant variable assignments themselves.