I solved the 50's on one side of the room by opening my inlet for the central air but behind a blanket. It keeps the air from crossing the room so quickly and it mixes with the intake air. Room is 65 now and raises 70 > for an hour before lights out at 12 noon.

Not scientific but... For now it works, after harvest I rebuild my intake system, add a/c for this coming summer and put my light fan on an thermo.