I have 2 Funtana 90's. Both are overpowered, one has a Saito 1.50, the other has the Saito 1.80. The one with the 1.50 has Hitec 5475 servo's with karbonite gears, the other has 5625's with metal gears. Neither has ever given me the least bit of trouble & flutter has never been an issue. Both will do knife edge loops so I don't think blowback is an issue & I have never stripped a gear in either one & both have had gallons & gallons of fuel through 'em. Whatever power the 5475's are, it's enough.

What I did do though is replace the cheap nylon control horns with some dubro's with ball joint ends. Having ZERO Slop I think is far more important then having $100.00 servos in your plane.