OK, thank you for that suggestion. I'll go with it. 4-pole, 2 dedicated to switching a relay.
Any recommendations for a 4-pin plug that isn't a threaded (MIL-type) connector? I keep going back to the 1/4" phono plug because it goes in deep and won't fall out and it's not a screw-in type. Of course this plug won't work here, but any such alternatives that are "deep" (actually go past the panel in this fashion)?
Thanks.