Thank you for relying the info my friends
Dave,
If you want, the plans for my modified pedal box are available for free download here:
https://drive.google.com/file/d/0B-i...it?usp=sharing
The reasons of why and how I modified the book's pedal box are explained at the beginning of the document.
The threads on my build blog are here:
http://vouchtroadster.blogspot.se/20...edal-box1.html
and here:
http://vouchtroadster.blogspot.se/20...edal-box2.html
I remember that Arfon made some improvement on the crush-tubes positions, you can check with him if you are interested.
Now, if you want to fit a double master/cylinder, you can adapt the design to fit a brake bias balance bar through the 25mm square section pedal shaft, I don't see any problem to that. But if you have the money, you can make it easier, and buy an OBP pedal box (kit-car model). They are directly designed to fit a double M/C, and are 240mm wide. I had some OBP pedal boxes in my hands, as the company I'm working for in France sells them, and I can say they look to be pretty well constructed.
http://www.obpltd.com/Pedal-Boxes/Kit-Car
Good luck!