Sounds like you got the info you needed but just wanted to reply...
My CV is mounted very high on the wall, about 13'. From the bottom of my CV to the bin is a couple of feet maybe 3'. I can measure if you want. It gives me a little more peace of mind too that I have more of a reservoir for overfill protection in case I need it, also I am less worried about my bag being sucked up high enough to cause any problems, unless of course it tears.
This hasn't happend by the way, and I do not use a bag retainer other than the locking lid itself. Somebody will probably chime in here and say I'm crazy, but I have been using this system this way for over a year and it works great.