The Promote will not work with the Second Shooter controller.
The Second Shooter plus has both and input AND output port, so that it can receive a signal from a 3rd party intervalometer. However in my testing with the Promote, I have not had perfectly successful results in bulb ramping mode, receiving triggers from Promote to our SS+.
The SS+ needs to receive a signal from the 3rd party device to let it know, it is ok for the SS+ to initiate the move. With the Promote, I had to use the hot shoe adapter of the bulb ramp assistant kit, then run a PC sync to 2.5mm cable from the PC sync port of the hot shoe to the INPUT port of the SS+. What I found is this would trigger the SS+, but for some reason, it did not seem to reliably send a signal to the SS+ for every frame. So if there were to be 24 images, the SS+ may only get triggered, say 21 times, and I have had that number vary.
I am having discussions with the Promote team, so hopefully in the future they will be able to reliably support the SS+ in bulb ramping mode.
However, at this time, the only bulb ramper, that we have confirmed is completely compatible with both the Second Shooter and Second Shooter Plus, is the RamperPro. Thanks