I've had Spuhr and I've had ARC mounts with levels that are placed at the bottom rear of the mount, for me this is too low to effectively see with my eye without having to break cheekweld; however, a more traditional level that is mounted around the scope tube is place at a position high enough to see without breaking cheekweld. That being said I have been trying to retrain myself to not use a level, but to level the scope to plumb based on my natural hold and allow my vestibular sense to correct, Thomas Haugland put up this video years ago and this subject was discussed on the old Hide (or possibly Scout) in length, I know for some it is difficult to think that we can hold level; however, I think more struggle and mounting the scope level to the rail and then struggling with their natural hold to correct. The evidence is there, it might be worth giving a try - go ahead and keep the level on the scope but find your natural hold and then adjust your scope/reticle to plumb based on your natural hold, then use the level as verification and you might just find that you can find natural level more easily. Those of you who have stocks with adjustable cant don't have to worry too much because you can level your scope to the rail and then you adjust the cant of your stock to your natural hold so that the scope/reticle is plumb when you naturally should the scope and get proper cheek weld.