How low should it go?Would it be ok if it was right on top of the bottom skins where the come together.I will drill a hole right at the bottom of the transom.

I built a rudder and bracket and i want to have equel turning both directions because i wont be racing this boat i'll be just having fun with it of course high speed passes .So i want to mount the rudder directly center after the prop.
How far from the props trailing edge should the leading edge of the rudder be?