The Quick Grip is exactly what I was looking, camera bag on, pure grip and sitting (mounted on a 6D).
He is well padded and so far very comfortable to wear.
If you want to QuickGrip attach the first time that's been a "Fummelarbeit", but if you have only once set him on his hand is the exchange between QuickGrip and tripod plate in a short time possible.
After 2 weeks, still sitting all Bombenfest, so far no signs of fatigue to see (have him now still not too long in use).
At the moment I can the Quick Grip friend.
