Progress is steady, just these last stages seem to take longer than anticipated.
Sanded down some off the two edges to make them smoother on the sides. The switching unit is working really smoothly also now.
Been working on the connector for the controller and to the case. Thought i'd share some pics and what i'm working on:
Figured i'd put in a couple of fans to move the air around the case itself. There is plenty of air intake from the switch section, and there is a strong air extractor at the bottom of the case, so there would be air movement, however had space for a small fan at the top and a 4" PC fan at the bottom (left) to move the air around.

I've been using a male/female connector to connect the controller to the base unit, easy to remove so I can move the base unit around my desk easier.

Most SNES controllers are molded and some are pretty much on the connector permanently, however I had a third party one that pops out from two clips at the back - ideal! Just need to cut off the end of the SNES connector to make it flat.

Got a male and female d-sub pair of connectors as need about 12 connections from base unit to master controller.
Idea is the connector will end up looking like this:

You can see in the photo the placement for the male connector.

When this is done, I then need to do the new power on/off switch, using the GameCube one instead of the bulky one I have been using.