parametrics and extra square?

[rodread]

Hi
Wondering if you have the parametric development file for this?

I might have to copy/ remake it in rhino grasshopper (my favourite) Grasshopper parametrics are a joy
Considering making a version in a thinner material
A local tech with a laser cutter only does up to 9mm mdf ... So I'd have to adjust all the slots
And the cutter bed is only 600mm long So I may have to adjust the base plate

Also
The component On the bottom right hand side of the .3dm file
Does that have an extra square outline shape in the middle which isn't meant to be cut out?
Thanks