Update: found the steering lock setting under the "garage 1" tab (where you adjust your aero, etc,), set it to 33 (max) and my Fanatec to 540 SEN and now all is well. I can steer properly and now can see why this game is so popular.
Edit: I set the Fanatec SEN back to 900/off and like it much better.
So some cars have more or less than 33 steering lock? Eh, at least I know how to get them dialed in now, shouldn't be a problem. Now if I can just figure out how to adjust for bezel width I'll be in good shape!