Originally Posted by
Steve B.
If you are NEVER moving to 2X on this system, I think they make a specific L shifter for 1X systems that has no Di2 function. Thus no need for an E-Tube wire to that side. My XT Di2 system has the bar display, a cable to the R shifter, one 1600mm cable from the display to the seatpost battery, another 1600 to rear derailer. Also saves on a B Junction.
Yeah, I too completely gleaned the fact that it was going to be 1X, hence no need to get a connection to the left brifter.
The OP seems to think he absolutely needs the Y-Cable (I’m sure he has his reasons), but I think the above is the best advice for a permanent 1X system.