Waterproof Case Adjustable Size

I needed a waterproof box for a solar charger I was designing.

I decided to make the design adjustable to allow the dimensions to be changed.

I updated the design as there was an error with one of the dimensions, which stopped it from scaling correctly!

Uploaded the wrong version last time sorry!
I have revised the design to include 10, 20 and 30mm M3 screws to be able to see what it looks like. Just enable one screw at a time!
A simple rule to follow is made the Depth parameter 3 mm less than the screw length you want to use.

Update 2018-05-03 It looks like the one of the extrusions had crested a new body, which has now been corrected in V9, thanks to Angelo Macaro for pointing out the problem.