My experience has shown that a YS will turn a heavy APC just as fast as it will turn a Zinger. So go for an APC 16x6. As far as run-in, I've bought all of my YSs used, so I can't help you there. That downside that diablokid mentioned has been a plus for me. All I know is that when the engine starts acting goofy, I refer to the manual, and set the high-speed and low-speed at 1 1/2 turns out, and the regulator flush. That is a very good starting point. Also, the high-speed and regulator have a very fine adjustment, so it doesn't take much. Here's an extremely helpful website for a new YS owner;
http://home.comcast.net/~mark.fuess/ys110.htm
Concerning my friend's UCD, he set it up completely according to the manual. I didn't notice a need for additional right thrust when I flew it. As far as fuel consumption, I get 10 minutes of 3D with an 11 oz. tank. The UCD owner says his YS gets
much longer flight times than any of his Saito 100's, and he has a few. The key to making a YS run good is smoke. If it looks like you're running a smoke system while hovering, the engine will run like a top. Be very careful when tuning the top-end. If you get it too lean, the engine WILL detonate, meaning it will try to reverse direction at 9000+rpm. This usually results in a thrown prop, and the destruction of anything in it's path. If you are tuning the top and you're turning, say, 8800 with a 17x6 (just an example), and producing good smoke, don't try to lean it out to bring up the rpm. Try a smaller prop. It took me a long time, plus countless dead-sticks, to figure that one out. Good luck!