To get the magnum for Jill, you must get the wind crest from the bee specimen room. When you get to the courtyard, use the red and blue weather vanes (N, S, E, W...) In the next area, turn to Jill's right until you reach two grave stones. Use the wind crest on the right side stone and get three more crests. Examine the backs of these crests and lines should come out of them. Then, use them on the left side stone. BINGO!!! You got it... (You can also takes Barry's if you really want to...)
-This also works for Chris. (Not the Barry thing, though... LOL)