Di2 wiring advice Tarmac SL6

[Archie100]

Managed to get hold of a new s-works Tarmac SL6 disc frameset (size 58) recently and was able to source new 11sp Dura Ace Di2 shifters/brake calipers/deraileurs, battery, junction A, junction B, S-works power cranks, stem and Aerofly 2 bars to build up the bike. I don't have the frame delivered yet so can't measure for EW-SD50 di2 wires so was hoping someone has built up a size 58 that can advise on cable lengths. Measured roughly off another make of bike, size 58 and was thinking of the following wiring:

1 x 650mm from battery in seatpost to Junction B near bottom bracket
1 x 350mm from front derailleur to Junction B
1 x 650mm from rear derailleur to Junction B
1 x 1200mm from Junction B to left shifter
1 x 650mm from left shifter to right shifter
1 x 350mm from right shifter to Junction A in right hand bar end
1 x 150mm wire for D-fly unit (was going to put this inbetween right shifter and Junction A in right hand side of bars) - would anyone recommend a better place to put this on an SL6?

If anyone can confirm the measurements from experience and best place to put the d-fly unit, that would be much appreciated
Thanks.

[idinfo68]

Hello, measurements are correct.
best place for D-Fly unit is near the Junction B near bottom bracket with bubble wrap around to avoid noise, same for junction box B

[GregR]

Use a Y wire in the bars. Connect the d fly to that. Try to get it as close to the center as possible. That way you'll get the most reliable connection to your bike computer. I have mine in the bar end and its connection to the bike computer seems to drop then reconnect a lot. I'd think that having it farther away would make that worse.
I'd go junction b to dfly, to y, with the other two branches to the left and right shifters. Then go from shifter to bar end.

[Archie100]

Thanks idinfo68 and GregR for your replies and advice.
My last Di2 build didn't use y-connector cable and it left a cleaner cockpit wiring to shifters so I would like to avoid using y-connector this time.
Maybe I'll try to keep d-fly up high in the downtube, e.g. wrap it in some bubble wrap near the cable guide cover so it's closer to the computer than down near bottom bracket. Will see how the bluetooth connection works there.
Thanks again.

[Dannnnn]

I'd avoid using the Y connector.
Especially with the Aerofly 2 bars, it's a massive pain to get inside.

I have a SL6 with Aerofly 2s and have
Junction B to LHS Shifter
Y cable from LHS to RHS shifter (not using the split off the Y)
Right shifter to Junction A
Smallest Wire from Junction A to D-Fly

I have no issues with the D fly in the drop on the RHS of the bars.
Maybe a touch of rattle but you can sort that with foam or cable ties.

[FIJIGabe]

When I wired my Emonda, I used a shorter, 250mm wire from the shifter to the D-Fly unit, then a 1000mm wire from there to the Junction A. This places the D-Fly as close to your head unit as possible, and I've never heard a rattle from it (my bars are 44cm bars, BTW).