Good Afternoon Melthmothtw:
A long time ago I was on one of first transition courses on the A-320 as a B-727 F/O to A-320 F/O.
It only took about 15 minutes in the simulator to feel comfortable with it and the same years later transitioning as Captain to the A-320 from a B767 F/O and the A-330 from Captain on a B-767. The one things you did have to watch for was the quick reaction to control inputs and not to "stir the pot"!