Quilt Planning Challenge - have the fabrics, now to decide on the design so I can cut them up and sew them back together again!

This quilt is destined for my nephew... he is smart, funny, sweet and deserves something special.  This one has been in the PIM (Project in my Mind) stage since last summer. I did the "Waves and Flips" quilt first.  

I wanted to capture his area of study at University - which is related to Network Security and whatever else is related to computer networking - as well as his school. We went to a local quilt shop together and he selected the first 2 fabrics, I picked out the others. So now we have 2 sets of green and gold, and a few novelty prints related to the internet. 

I have been particularly taken by modern geometric designs, interwoven pathways. I am being inspired by "mother boards", computer chips, workflow diagrams. Now I have to make the math work. 

It would be simpler to pick a pattern on offer but somehow, for this guy, I want to do it all. 

This is the design planning flow so far...

There are a few interesting ways to play with these 2 colours.. I can view it as a monochromatic quilt and leverage the contrast seen through the shading... or I can plan it as a 2 colour quilt... how should I alternate the colours?

The next question is size. The end result should be suitable for a double bed so around 66" to 72" wide by about 72" long.. or so

The pathways should be  2 1/2 or 3" wide...Too bad for me that my version of EQ6 seems to max out at 24 blocks wide and long. I tried to colour this as 3" blocks. 

Watch this space for my progress!