What Indignation said is correct. Use sharpie on the edge bevels. Then do some strokes at 30 deg on the sharpmaker. Look at the edge bevels to see where the sharpie is being removed. If it goes all the way to the edge, then you can use the sharpmaker at 30 deg. If it's only being removed at the *shoulder* of the bevels, then your bevels are greater than 30 deg. Switch to the 40 deg setting, reapply sharpie, do a few strokes, and check the bevels again. Same drill: If the sharpie is gone all the way to the edge, you can use the 40 deg setting. If not, the you likely need to use a bench stone or something like the diamond rods for the SM to bring your blade's edge to 40 deg or under. Then you can use the SM for maintenance.
Good luck!
Brian.