placing probe for thermostat

I have two balls in two seperate tanks. i have zoo med uth on them now and i placed my thermostat probe inside the tank on the glass above the heat mat under newspapper and then i have an inch of aspen on top of that. I put newspapper under the aspen to be safe and not burn my snake. I have my Ranco thermostat set for 110 and the dif at 1. It has been keeping the hot hide between 88 and 90. I was wondering if this is ok. thanks for the help.:)

also wanted to know how i should run the probe wire out of the terrarium..

I would just put the thermostat probe out the outside of the tank directly on the heat mat. Then just have another thermometer of some sort inside the tank to double check the temperature on both sides. That way you won't have to worry about the cord for the thermostat and it might control it more accurately.

I keep all of my Ranco probes outside of the enclosures directly on the heat mat (or Flexwatt) because you never know what the snake is going to do... some of mine have a real talent for absolutely destroying their enclosures. If they end up moving the thermostat probe in the process, you might cook them under certain circumstances.

Keep in mind though if your probe is on the heat mat, the thermostat temp might not be exactly what you want the hide temp to be. For example, your heat mat might read that 110 degrees, but through the aspen and all of that fun stuff your hide might only be 80. That's where the backup thermometer in the cage comes in handy.

Ditto, just tape the probe on the outside of the heat mat/flexwatt with some aluminum tape because it's more heat resistant than plastics, and use a thermometer inside (or infrared gun) to double check.