Mine is on a Johnson quick release lever which moves it up about 8 inches off the deck and mast, but the bottom mount isnt changed

Couple comments
1 I start with the halyard and head of the sail as far up the extrusion as I can - when you pull the sail luff taut and stretch it down it comes about 4 inches in my experience.
2 The slot in the extrusion where you feed the boltrope is about a foot above the the ring in this picture - I push the bottom bolt rope down so that the entire bolt rope is in the extrusion. You have to bend the sail a bit to get this done but it will give you that extra 0.001 knot speed.
3 Note the pin/ringding on the green plastic cup - this is the one you remove to push the cup up the extrusion to check your bearing/turnbuckle

