is there too much elevation possible.Cant sleep unless I elevate my feet.

You cannot elevate enough. Don't know about you, but that gets old really, really fast. I sleep w/leg elevated, have a recliner where I elevate my leg somewhat, but...it's not enough.
Deciding your effectiveness and comfort level tho? That is easy...make a point of looking at your leg before 'elevating' when going to bed. Then take note when waking up [yeah I know the waking up part is HARDER!] But, IF there is a difference? You mite talk to your doc about other ways of keeping the swelling down [which I'm assuming you are having?]. Often, simple physical therapy or exercises can help get the circulations going [blood and lymph systems] and help reduce swelling...IF you find good Therapists. That IS a whole other kettle of fish!
's Anything to keep from viewing the world on the tube from between yer feet! - j