Thought it was about time to give a little update, as a few things have been changed. Found a matching big post RDA which has made me a very happy bunny.
I am currently running 0.13ohm quad coiled Royal 26 micros, which is hitting aprox 90W and running nicely indeed.
I finally got a pair of VTC5's in there and they have been great, low ohm builds have been getting about .2v less drop from the VTC's compared with the AW's so that has given a good power boost on 0.2ohm coils(about 7watts extra).
I have had a few issues to deal with.
The slide switch had to be replaced as it was not always making good contact(I had a few spares and they were the same) so I fitted a real nice quality mini toggle switch I had kicking around from one of my amps. This means I am now getting full power to the FET gate which was causing issues.
The FET has been working a charm with sensible-ish builds (0.4ohm+) but with silly builds below 0.2ohm the FET is not getting enough gate voltage due to high volt drop on the batteries at around 100W. On a 0.13ohm coil I am getting 0.7v drop on the VTC5's. So the FET has now been changed for one which will fire with much lower gate voltage(2.35) still 92A rated so plenty of power handling. This seems to be working much better with the very high loads, and I can feel a big difference with my current build.
The first spherical switch died after being pulled around getting stuff in and out so many times, then I ruined another so I am now on spherical switch #3. So I will be a lot more careful with them!
This is the FET I have fitted for reference:
http://docs-europe.electrocomponents.com/webdocs/0f35/0900766b80f35039.pdf
Hopefully this info will is useful/helpful.
Just need to figure out this low ohm building trickery, I just cannot seem to get anything below 0.1ohm