Success, I got the housing all the way from the seat tube to the back of the chainstay. I know a lot of the appeal of this project is just how tinkery it is.

I measured out all the wires:
shifters to A junction: 350x2
A junction to B junction: 1000
B junction to FD: 200
B junction to RD: 700
B junction to battery: 550

Those are best guess at the actual distances. I'm sure I should add something to each for safety margin. 50mm? 100mm? More?


BTW I used a borescope to help get the housing through. I use this tool about once every 2-3 years. Every time it is like "hey I have exactly the right tool for this!" and I am so glad I have it.