colotandem

I'm investigating Di2 for our tandem. I searched and found a few different threads that have found various debates the merits of Di2, some people's bike builds and a few other useful items. But was hoping to find the detailed specs - of course they are not all in one place. Also, some people have upgraded and/or changed their setups.

I was wondering if there would be an interest in providing your latest iteration of Di2. Feel free to add/change the list below. What am I missing? I am not a user, but am thinking about it. My hope is to have a source thread that users and prospective users can reference.

Chainring specs (i.e. 52-36)
Cassette specs (i.e. 11-36)
Deraileur specs (Ultegra xyz model & cage length)
Shifter specs
Battery specs & placement
Junction box(es)
Display?
Brakes
Cranks
Rear spacing

Any major issues with implementing your set up?

Any items that you intend to change (based on existing technology - not the hope for 3x road etc.)?

Thanks in advance for those who wish to contribute!!