According to this : https://www.lrl.usace.army.mil/Missi...Green-Profile/ .... I wouldn't fish any deeper than 20ft, and would probably start at the 10-15ft depths (where the water temps make a significant drop of around 3degrees F.
Mind you, though ... these readings are taken at the dam, so there is a potential for slight differences in the area you're staying.
I know some people say to drop your lights several feet below the surface .... but I've never understood the reasoning for doing that. The lights draw in Shad (to feed on the plankton drawn in by the light), and the Crappie are drawn in by the vibrations of the circling Shad ... and since they will hang out below the Shad, or just on the outside edge of the lighted area of water, why would you want to put the lights down deep ?? And, also by doing so, you run the risk of a fish getting your line tangled into the light's wire.
I'll admit I'm "old school" ... and brought up using a Coleman gas lantern for night fishing for Crappie. And the current way I do it is with a "12v headlight/styrofoam" surface light. Both of which still work very well.
The only other thing I can think of to mention, is to remember the creel limit is now 20/person/day ... but, the size limit is still 9in.
Luck2ya !!