I leave my blower running at all times to circulate air in the house and help keep the temperature relatively constant throughout. I also leave all the interior room doors open to help promote airflow and aid in the temp balance.

I knew that the humidifier would not control the blower. A fancier thermostat would allow programming scheduled blower cycles instead of leaving it on all the time as well.

The humidistat should work in the same way as the one with my current unit. It attaches to the cold air return duct and monitors the humidity there as an indicator of what the humidity is in the house as well as having a probe outside the house to monitor the exterior temperature. Depending on what it reads from both sensors and according to your dialed-in setting, the control module within the humidistat unit will turn on/off the water supply to the humidifier (my current model doesn't have a reservoir). So basically you set a humidity "level" from 1 to 7 to achieve a range of relative humidity in the home. You have to play around a bit to get it to balance out so that you're not left with condensation on your windows. Once you have this sweet spot you can pretty much leave it set at that setting. The actual relative humidity within the home will then go up or down automatically depending on the temperature outside.

The setting will be different for every home of course. It all depends on how humid you can keep your place without causing excessive condensation. The colder it is outside, the better insulated everything needs to be to prevent the inside moist air from condensing. Our windows are double pane low-E argon filled, but I still think they're pieces of shit.