of course it depends on your flight expierence but for a 91fs a 14/6MAS is a good start I like the plastic composit props they do have alot of flex in them but one prop strike and you are replacing the wood ones until your used to flying a particular plane start with a plastic or composit prop all the props you have listed will work it has alot to do with ground clearance the wood ones have alot less flex in them but they don't last long if you are not making perfect landings.