Big Pistons, I enjoyed your last post there. Only clarification would be, which Vx? If I bought an aircraft, or flew it regularly and had time to kill one day, I would go and test it and establish the correct values of Vs etc and then all the others that follow, including the climb speeds, but I think it would be better for our original poster to use the POH figures, which should be conservative at <MTOW or MLW.