Temperature differential

After running a furnace for about 10 minutes to heat up the plenums, what do you find is an acceptable temp difference at the registers from different rooms? Room 1, 110 degrees, room 2 (right next to it), 95 degrees? How about from floor to floor. Just trying to find a basic rule of thumb. Thx

There is none.

There is more to it than a dry bulb temperature reading.