I have been shaving with the one hand for almost 3 years now, the main issue in my case with shaving with one hand is the first with the grain pass on the opposite cheek. (your right cheek in your case since you are a lefty) it is hard to get it as smooth.

With that being said, when you re-lather and take your second across the grain pass. It will all even out to be about the same on both cheeks.

I recently tried shaving with my left hand for that cheek and I must say, I got much better results from that first pass so I am slowly incorporating it now into my shave. I dont regret learning with one hand to begin with and then trying the left hand, I know a lot more about angles and pressure now so its kind of a safer approach.