Hi, welcome to the forum. I would say that you need a caseback opener at least to do this fix by yourself. Arm yourself with 1.2mm screwdriver should you need to release the stem on ETA2824/36 movement. If you use Chinese DG movement, you need a pin to release the crown. However just by tilting the retainer ring a bit, you should get a good alignment. Check your crystal too, it maybe crooked hence it appears that the 12 and 6 don't line up. You also need silicon grease to apply at the gasket after you are done fixing.