1x SW-R600 or 2x SW-R9150 is totally personal preference I guess...I like to shift on left and right hand side, I'm used to that. Also, the SW-R600 is a bit bulky to me...I really like the small size of the R9150s. And yes, SW-R600 requires only one free port.
R9150's cable length is 261 mm. I mounted the switches right at the end of the base bar, the cables then are just long enough to go inside the base bar until the stem's opening. I connected both cables to a SM-JC41 which hides within the stem. A single cable (~200 mm) then goes to the junction box which is placed in a bento box behind the stem.
R9150's cable length is 261 mm. I mounted the switches right at the end of the base bar, the cables then are just long enough to go inside the base bar until the stem's opening. I connected both cables to a SM-JC41 which hides within the stem. A single cable (~200 mm) then goes to the junction box which is placed in a bento box behind the stem.