M_Boats: Whisker pole mounting point on M17

Good morning all, So far it is looking like a nice start to September in this area (Ontario). We are heading to Lake Champlain for Labor Day weekend till later in the week. Then up to the Ottawa River at Arnprior. I have looked through the list archives searching for whisker pole info. Some references to the different types of poles (mostly Forespar). My question is how do I determine the vertical height on the mast to install a fitting to hold the inboard end? Has anyone a done this, or have a link to refer me to so I can calculate it? I am thinking to just put a single eye, instead of a short length of track. Thanks, Bill Wickett M17 #622