Hey man
I switched to the one-hander just over one year ago. It was a great decision. One of my best coaches got me thinking about it and I did it. My athleticism could never really show in my two-hander. I feel much more confortable with my one-hander now. I can be very versatile with it, slice, flat, heavy spin. I can hit passing shots down the line and crosscourt, something I struggled with with my two-hander(at least the down the line shot).
You must be very patient while learning this however. It will take several months for you to feel completely confident in it and it will take you a long time to develop hitting a consistent GOOD ball. Make sure you don't get into bad habits right off the start. Make sure you have your grip right, like Federer's backhand grip.
To answer your question, when I played my first tournament with my one-hander, it wasn't very pretty. I would switch back to 2 hands match in and match out and hit a nothing ball with my backhand. However, learning from different coaches and keeping belief in the new shot, I myself found new things I could do with it. I grew more and more confortable in my backhand and even though it isn't consistently a weapon, it is consistently going in the court without getting me killed. I continue to work hard on it and the variety of shots that you can hit with the one-hander is the key to keeping you comfortable with the shot and out of trouble.
About the return, I continued to struggle with it until 1-2 months ago. I was always defensive and had to scoot back to give myself time, but now I am moving in from the baseline by having a neutral grip that I can hit with my backhand and forehand. The grip gives me a strong western forehand while keeping my backhand grip just a bit eastern of continental.
Good luck with it, work hard and stay confident!