Sounds good to me. Do you mean Pro Products RHP for the AP cages? The ones from Bob? Those are really nice and that's the ones I use in my Proline Cage. Unless you see yourself needing all the power of a Herpstat 4, I would probably just use a couple Acurite thermometers/humidity gauges instead and save the cash. IMO having a Herpstat 4 is nice but if for some reason, it crapped out, you would be up S creek if you didn't have a backup. I would rather order 2 Herpstat 2s so in a worst case situation, you can use one as a backup. All those cages hold humidity very well. Im up here in Washington state and my humidity in my Proline sits around 60 with aspen and just a normal size water dish.