Merkur has an adjustable called Merkur Futur which is supposedly good, that way you get all the angles in one razor!

Other than adjustables, it's just trial and error til you find the right angle for your face & skin.

Personally I really love the Karve system, the angle plates are not horrendously expensive, so I just bought a bunch to try when replacing my old Merkur 34C (which I used for 12 years before upgrading). Turns out I like open combs way better as well, they don't clog up as much when shaving!