I am not upto date on e-tube software, but it begins to look like the ability to synchro/semi-synchro with the
appropriate battery and junction box will allow such as the SW-R9150 to control both FD and RD, but further
study is needed to see how far this functionality would go. If e-tube software can reprogram the SW 600
switch to control the FD, that would be a perfect solution to the op problem, as the SW600 can mount within
in thumb reach below the brake lever and give exact 2 button control of both FD and RD.

Carlton Bale's site is a good start: https://carltonbale.com/