I have tried it with panther and tiger, the problems I have experienced are the same. The resolution does not change automatically, but I have found another big problem: The game is still going back to the OS without any message if you try to "capture" a planet (or somebody does the same with one of yours). I can't even find a error message in one of the OS-logfiles. This makes the game unplayable, for myself I can avoid it to capture a planet (not good), but sometimes you can't stop the computer from doing so.
I too have an Ibook G4. I would be very glad if somebody has a solution (especially for the "capture"-problem). Is anybody out there who does not have any problems with this classic-game?