brakes and breaking are not a problem: on the front wheels there are two brake (one standard and one for emergencies). Disk brake is'nt possible due to the frame concept.
I'va right now talked with shimano tech support. I saw that in ultegra DI2 you can disassemble the switches from the brake levers. I was told that with some more work, you can remove the switches wired without cuttint the female connector. This is interesting for two aspects:
- if you have trouble, just reassemble and warranty is ok (no cut and soldering...)
- if you don't need any more, reassemble and sell as used.
The last aspect is to know if there is the possibility of use one only button for front derailleur, but it's not so important.
have one less cable and cable house turning is more safe and power saving too. If I can do wireless brake..
(OK OK I'm JOCKING!!!)