Terrarium temperature

Hi,I recently adopted a Ball python the tank is 36x18x17 I have a UTH of course but I'm trying to set an ambient temperature of 78 to 80+ at least on half of the tank I'm barely getting 77 I got 2 50 watt CHE right in the middle of the tank,hooked up with a thermostat also basking area is high 80,s to mid 90,s I have another 60 watt CHE I'm thinking on putting it either on the middle or on the side where the warm hide is,the room is kept at around 75F I have a 100 watt power sun for my dragon I have no problems keeping that tank warm lol I thought the 2 50 watt CHE would do the trick any suggestions?