I apologize for bringing this from the dead, but I have found that the coolbot is not necessary if you are willing to do some easy wiring.
An Inkbird ITC-308 would be more appropriate than the WIN-100. I have both. The WIN only cools down to 45 degrees, which is fine in your case, but the inkbird has a compressor delay, which is needed. Pulling the ac unit's temp probe away from the fins should allow cooler temps. Cooling down to 65 shouldn't create frost issues. I use an inkbird to cool below 40 degrees, and frozen fins are an issue at that temp. A coolbot isn't necessary if you don't mind doing some wiring. I bought two inkbird controllers and a contactor/relay ($90 total). I used the Emerson 90-245 120 VAC 30 Amp 2 Pole Definite Purpose Contactor. I wired the contactor to directly control the compressor, which allows the fan on the ac unit to stay on for defrosting purposes. At first I tried using a heater on the temp probe like the coolbot does, but you are definitely limited to certain ac units if you go this route. If you wire up to directly control the compressor, you can use any ac unit you want, and there is no on/off delay caused by using a heater on the temp probe. The two inkbird controllers are plugged into each other in series, and control on/off of the compressor. The temp sensor from the first inkbird is inserted into the cooling fins of the ac unit just like with a coolbot, allowing precise control of a defrost cycle based on fin temp and minimum defrost time. The temp probe from the second controller senses the room temp. The two controllers in series control the on/off cycles of the compressor by switching the contactor on and off. With this setup, the compressor only turns on if the room temp is over your set point, the fin temp is above a certain set point (32 degrees has worked for me), and a defrost cycle has been completed using the compressor delay setting for the controller sensing the fin temp. This setup is a lot cheaper than the coolbot, and works better than the coolbot because the delays in on/off control associated with using a heater on the ac units temp sensor are avoided. I actually use two ac units with this setup, running the compressor from each unit through the separate poles on the contactor. It doesn't take long to determine which of the two ac units frosts up first, and the temp probe for determining fin temp is inserted into that unit to control the defrost cycle. Using two unit gives a higher cooling ability, and shorter run times for reduced frosting issues. I've found that used 15k btu/hr units can be easily found for as low as $25. That's about as big a unit as they make without getting into a 240v unit.