Drifters is not a consistent monthly manga, you may not have known this, but looking up on the internet will give you a vague idea of how random Hirano puts out Drifters.

You can basically lump him in with Miura and Togashi of Berserk and HxH.

As for the raws, there's many places like senmanga I'm guessing, I'm not too sure because I don't know squat about scanlating so I never bother and I don't like spoiling myself! Very proud of myself to not touch the Kingdom raws for example XD

But if you already have the latest raws, there's....nothing you can do.