The Thermostat is set to turn on when the temp is below 92f and turn off when it hits 96f. This keeps the inside surface temps at what they are. Iv moved the probe to under the heat tape, and the temp fluctuations were pretty wild, it would heat up fast, and rise a degree or 3 above 96 even after shutting off, then it would cool off rapidly. I think this is because it is no longer against the thermal mass of the Glass. its just against the heat tape and air.

I now have the probe between the heat tape and the glass, but close to the end. so that rather then having the centre of heat tape tented, and not having sufficient thermal coupling contact, its at the end, where its still tenting the tape, but only about 5% of the tape, and maintaining a better thermal contact.