I use #4 sheet metal flathead Phillips in black oxide for tracks for RealTrax and FasTrack. You can get them from McMaster-Carr, MicroFasteners (out of stock now), sometimes Fastenal
I don't fasten switches. I fasten the ends of the three adjoining tracks.
I like the method that you are using to extend the switch control wires. Good for trouble shooting and keeping the equipment in factory condition. It takes a little more time now, but, it is a lot easier when changes or maintenance is required.