The only concerns I can see right now are
A) The temperature is too low. The basking spot should be 90F. The air temperature should be 80F.

B) Regulating humidity is going to be extremely difficult.

You will probably have to cover all but an inch of that screen top with plastic, and might still have to add a fogger (such as a Repti-Fogger) to keep the humidity at 60%. Covering most of the top and raising the humidity may also help with the heat issues.

Hot air rises, of course--and floats right out of the top of the tank. This is the reason why tanks with screen tops aren't recommended. You will need to modify this setup to provide correct temperatures and humidity, it simply can't work as it is currently.

Are the shavings aspen? Pine is potentially toxic.