I tested out the Rule-mate 750 in a bucket. The switch-less operation appealed to me. But it took a lot of water in the bucket to get it to turn on, and it turns off with more water in the bucket than I wanted to have in my boat.
The 750 is a different pump than you are talking about. There is a pump that turns itself on periodically, senses whether it is doing any work (lifting water) and turns itself off if not. That might work better, and maybe that is your pump. The 750 has some electronic wizardry that sense water beside the pump through some sort of electronic field sensory device--bad explanation, I know. But, I don't think it is suitable for kayaking, and it also would not fit behind the seat in my kayak where I wanted to install it. I still have it--let me know if you'd like to buy it half price.
I take my kayak on extend trips, and I didn't want the one that turns itself on to discover water. I feared it would run down the battery while I was away from recharge capability. Perhaps the power drain is insignificant and my fear was baseless, but that was my reasoning. Also, I don't have a check valve in my pump outflow, so there is always going to be a tube full of water that runs back into the boat. Would that be enough to make the pump think it needed to pump again, and if so, it would cycle endlessly, because there is always going to be that last tube of water.