I dont know much about olympic lifting (new here), but i do know something about strength training. I think if you want really stable shoulders without it taxing too much of you. I would so something like this:
1 Arm dumbbell strict overhead press (also trains core) 3x8 each arm
(incline) close grip bench press (take the width you use for pressing overhead) 2x5
Pull ups (stronger arm and lats, help with overhead stabilizing) either 2x5 for strength (add weight) or 3x8 for bit more mass
This is just for your shoulders and a bit core, since you are following a 3 day/week oly program you might be able to do 1 exercise after each workout and have your 4th day some general strength training?
hope this helps