Humidifier Info

[tg]

Looking for do's/don'ts or suggestions on humidifier.
I'm looking at a unit from www.dspringair.com right now.
This will go on a heat pump.

I have a dual system. The larger unit runs the two lower house levels and a smaller unit runs the two upper levels. I'm going to put this on the lower unit (mainly because that's where the water lines are easy to get to).

Anyone had experience with type of setup or with this unit, would appreciate feedback.
Wonder if I'll have to install a second unit on the upstairs system?

Thanks all
T.O.