shower stall ceiling
You shouldn't have any condensation issues with the exhaust fan.
We have exhaust fans in our bathrooms with timers as well. I can tell when the wife doesn't turn the fan on until after her shower because there is a bit more moisture on the crown moldings, but I've never seen any on the ceiling.
The nice thing about the timer is we hit the 30 minute button before entering the shower. It seems to be the perfect amount of time to get the moisture out.
A DIY Noob that knows just enough to be dangerous.