Hi badger
I can't answer the first question.
On the second question, the SWG should be wired to the same power supply as your pump. So if pump is on SWG is on. In our case that is the timer. The SWG is on when the pump is on. We can control the percent of time the SWG is actually producing chlorine via the SWG settings in 20% increments.......meaning is it producing chlorine 20% of the time it's on (with pump running) or producing 40%, 60%, 80 or 100% of the time. That is an adjustment you'd want to make along with your pump run time.
Third question.......yes. You can shock (SLAM) at lower cya. It is easier to do so as a matter of fact.
As and SWG owner I can tell you that when SLAM is in order, I usually shut the SWG off and manually add chlorine. But for regular maintenance once cleared, the SWG is nice.