I had a YS91AC on a Morris Hobbies 60SuDoKhoi. I was using a modified Zinger16x6 prop. Unless it was a hot and humid day (as hot and humid they get here in Los Angeles) I could pull out of hovers with no problems. On the H7H days I would have to fly out of a hover. The YS91FZ is probably a little stronger, and with an apc16x4W it should develop somewhere in the 9-10 lbs range of thrust. I at the moment fly a 6.25 lbs plane with my YS91AC swinging an apc15x6, and it rockets out of hovers.
DKjens