In summary the build consisted of these steps.
Drill into end of chainstay (aluminium lug) to allow cable end to pass through (approx 7mm hole),
Hole opened up for FD cable to allow end to pass through from under bracket to opening in seattube. the seattube elongated hole needed very little opening and I was careful to smooth the hole edge to miminise stree raisers.
I drilled a hole through from the BB underside and through the top of the BB to allow my battery cable to pass through. In hindsight I would have drilled it smaller, but it was large enough to pass the batter connector through.
I drilled a hole horizontally through the BB to allow access into the chainstay.
I mounted Junction box B under the BB using velcro and ensured it was away from the operation of the brake cable. Next time I have the BB cover off I will post a picture.
So from one end of the Junction box the FD cable ran up to the BB and the RD cable doubled back and entered the BB through the bracket hole. The battery cable ran straight into the BB and around the BB inner shell as did the RD cable.
To get the cable through the chainstay caused me a lot of grief and eventually I bit the bullet and cut it and spliced a flat telephone cable in, which allowed it to get past the RD cable guide tube which is bonded in.
Non of the cables under the BB are visible from outside and every hole if drilled through metal not just carbon.
For the cockpit I opened up the gear entry on the top tube per Cervelo recommendations.
All the switches were Cateye computer switches and I made a male connector for every one. I didn't cut any of the aero cable.
It took a bit of thinking to work out how to run the cables through the Easton bars but essentially the Junction boxes are inside the aero computer mount and the base bar cables enter the aero bar and route to the outside.
The base bar switches are mounted over the top of the brake levers and held with cable ties under the bar tape, but I used heat shrink to cover the switches.
Feel free to ask any questions and I will attempt to answer.
Oh, and the other thing. I did the whole lot for $1400!