Well I was using a 4s YS91AC and I tried props from a 14x6 up to a 15 x 8. The 15x6 Zinger Pro was probably the better prop in my opinion. It would run up well and deliver sufficent power and speed to fly the plane. I think a 2 stroke should be a great (hover) power system. It will also keep the weight down. I saw that somone got one of these flight ready @ 7lbs which is a full 2lbs under the weight of the Staud. So I would say a 91 2s should be the ticket, if it is a 4s I would definately go 120.