wakesurf rope length and speed

i am new to wakesurfing and was wondering what length rope i should be using and how fast

A good starting place is 10mph, adjust speed up or down from there to clean up the face and allow riders to stick in the pocket. My rope length is about 20 feet, you just want enough to allow riders to get into the pocket without the risk of getting the excess tangled around the riders arms or feet.