Is your Di2 Ultegra, XTR or XT? If Ultregra, did I understand correctly that it will shift the 42 tooth cog without the Wolf Tooth road link? I ask because I have Di2 Ultegra and I'm concerned that 50-34 chainring and the 11-34 rear is not geared low enough for steep hills. That is a great looking tandem and I'm sure it will serve you well. I also like you XT gear display. Many thanks.