The swx_1 open doesn't always get the PMUP to turn on, since the PMUP has it's own set of rules (like how often, max time, etc). So if you can get it to be triggered the same way, I think that would work well.
I just think it's overkill and really not needed. Solenoids can also fail, and I've heard need it's own set of maintenance.
A simple siphon break is all you need. A tiny hole or anything right above the waterline in your reservoir will immediately fix the issue. Drill a 1/8" hole into the line pointing back down into the water. I only had a 1/4" drill because my siphon break connector's hole came without being drilled all the way through, and I made a hole twice the designed size. Still works fine, just a lot of water shoots out. My ATO reservoir is covered well enough, so no water gets out.