I have just tried a lot of different props, with the exception of Bolly, Mejlik, Menz. If you can get 19-20 #, let us know what prop you achieved it with. I have used a couple different thrust calcs and haven't found one that is really accurate.

P.S. A Bisson pitts muffler and a V-30 Perry pump will substantially increase performance and mileage on the 160fx.