I fly my YS 110 with the 16x6 APC. It gives more thrust than the 17x4W. I use the 17 when I want to do a lot of hovering. It's easier to hover but doesn't have the thrust of the 16. If you are below 2000' elevation or so you can use the 16.5x5.5 APC that is special made for the YS 110.

The UCD has a wide range on the CG. I run mine at 5 5/8" back and I love it there. It is very easy to hover and allows some precision maneuvers like rolling circles. You can go all the way back to 6" but I don't know what you would gain.

You'll love this combo. Make sure you don't over speed the plane with the mighty 110. Never!

I was just flying mine today. My favorite airplane. I love it.

thanks
Barry