I've spent the past couple of days trying to get my temps dialed in before my snake arrives Tuesday and I'm having trouble keeping the cool side in the low 80s during the day. My current setup is a 36x23x14 pro-line cage from Constrictors Northwest and a 55 watt Pro-Products RHP on a Hydrofarm thermostat (upgrading in the near future). I'm also using the AcuRite thermometer. The thermometer body sits on the cool side and the thermometer and thermostat probes are hanging 3/4 of the way down the wall closest to the RHP. With the thermostat set to 90°, the warm side fluctuates between 88 and 90 day and night. During the day the cool side stays around 86 and drops to 83 late at night. The ambient room temperatures are 75 late at night and 78-82 during the day. The humidity in the enclosure stays between 55% and 60% constantly. I don't currently have a temp gun, but I can order one via Amazon and have it here in two days. Any recommendations?

Here are my current readings
Warm side: 90
Cool side: 87
Humidity: 57%
Room: 80

Should I add a couple of vent holes on the cool side? If so, where? Top, bottom, middle, etc. This will be my first snake and I want to have everything as close to perfect as possible before he gets here, so any help would be greatly appreciated.