Minthalas
Phoenixliv
If you have the cash, go with carbon fiber. I got mine for about $100 on Craig's List and it's amazingly stable and light for it's size
smile What brand is your tripod? And does it use a hex-plate?
It's a Davis & Sanford and it has a quick change adapter (but it's rectangular) It stands about 5'4" tops so my camera makes it about as tall as me and it's about 15 lbs