I'm not sure what functionality it provides. Next paycheck I'm definitely trying it out, though. I'll have to record my current averages in temperature and humidity, then record what I get afterwards and post it here for your evaluation.

I haven't tried Ultratherm pads myself. Open a new thread and title it 'Flexwatt vs. Ultratherm' and create a poll to see how many people use each. I'm interested to know.

And yes, Substrate > Glass > UTH > Thermostat Probe

Like I said, I think that putting the probe between the glass and UTH like (Substate > Glass > Probe > UTH) creates a loss of conduction between the UTH and the glass. So if you set your hide over the center of the pad, it would be on top of a zone that doesn't even have direct contact with the glass, you're just counting on the heat rising into the glass. I'm not sure if it has any major effect, maybe a loss of a degree or two, but I think it makes more sense the way I have it.