Parametric 2-slit buckle

There are number of things of the kind on Thingiverse but (again) I could not find a design fully satisfactory to me. Hope this helps somebody else.
The uploaded STL file has 30mm gap length - I guess you will have to change it.
Note that the uploaded version has max_height = mid_width and side_height = side_width; though the script intended to manage arbitrary proportions I did not test it myself.