You will never make everyone happy, due to timezone differences. A solution I see, could be to randomize schedule for Abyss/Undead/BigMaze on a weekly basis. This is not something the GM does manually. This is something that could be done automatically (random RNG).There used to be a war screen in-game (z hotkey) that would show times. All you would need to do is add that back, and have the server update times every week. Jill could come up with some IF/THEN statements to make sure these mazes are never back to back.
The main goal should be to think of ways to force players to login, be active, and stay active. Catering to a specific timezone will only attract those players, and the rest of us will be forced to quit. The goals should consists of content for both PVP players and PVE players, and try to eliminate the scheduled in-game events. Players should be able to login, and find something to do to keep them engaged. We find it all to often, that people login, and go AFK immediately, because there is nothing to do. We need to change that!