Humidity is recipe dependent, Camembert's like very high initial humidity to get the mold to bloom. Most people like 85%, to measure this you need an accurate gauge, there's a few posts on gauges in the Equipment Board. If no gauge then I go by condensation, lots and humidity is too high, none and too low. But that is quite crude.
Some household fridges will not run at warmer 55F temperatures.
You'll need to slow dry it, if your cheese is yellowing at edges then surface may be drying faster than inside which results in cracking, click on picture in top right
to see an example of rapid drying. There is no rush to waxing.
I've never made cheddar but 64F seems a little warm, can anyone else advise?