I use the one piece mount, and can say that in normal shooting according to Spuhr you should be using your non-shooting eye to see the level, not repositioning your dominant eye. In that case I will tell you that no, you cannot see it with a left dominant eye, at least when I just tried now. If I dropped my eye and face I could, but it is also blocked by the eyebell of the scope from your dominant eye. Your right eye will not be able to see it either.
I would think maybe ask him if he can fab you one up with the level on the right side of the mount, rather than the left, so you can see it with your right eye. He is known for his customer service, so he should be able to.
Otherwise get no level and add one.
I would say that Spuhr is the best mount I have seen in some time, nicely made, great modularity, and when I got mine I bought spare parts too, which is easy to do, incase I lose a screw or the like.
If in doubt about height and clearance issues, I would suggest emailing him, he will answer in person. I do believe his mounts are all geared towards clearing the 56mm scopes, but in my case I mounted a 42mm, but it looks like a 56 would fit.