Ok as long as I read and test what you need is not supported yet by Catalyst architecture:
//trying to do pixeline with extra channels on the end.
// doesnt work with architecture
// <extrachannels index="1" fixedoutput="7" />

So long the solution I propouse to you is:
patch a custom fixture named EGFix place it anywhere you want on your grid that does not matter,
patch 4 RGB pixels in the order of your floor (my reason to patch pixel by pixel is the strage arrangement of your fixture matrix:
3,4
2,1
as long as I tried Cat only arrange pixels:
4,3
2,1
Maybe there is a way for make it your fixture way but I did not find it),
patch another EGFix
patch 4 RGB pixels in the order of your floor,
and so on...

I know this is a dirty way to make the workaround but due to architecture at the moment I think if a good solution.

Here is your EGFix to add to your XML file so you can patch EGFix:


<Fixture menuname="EGFix" uniqueid="EG01" excelexportid="EG01" pixelwidth="1" pixelheight="1" output="CUSTOM" comment="Made By Wodie" channelcount="1" channelsperpixel="3" orientation="BOTTOMRIGHT">
<channel index="1" fixedoutput="7"/>
</Fixture>

That is all I think if you have further questions or any one have any comment please let me know I really preciate feedback.

Have a good show and let me know if it worked.