Sadly my old tripod, although sturdy enough for most jobs buckled and moved under the extreme weight of my sigmonster.
Two weeks ago I found a surveyors tripod for £10 in a car boot sale.
I made a quick release shoe for the lens and then built the convertsion to turn the top plate into a camera/lens fitting.
The quick release is 100%. There is no movement at all because the cam pushes the foot plate into a recess with downwards force.
The tripod is very much lighter than it looks,,its much lighter than than the lens.
For height adjustment and leveling it is no slower than modern tripods mainly because there is only one leg to adjust and the cam levers are adjustable so you don't need to struggle using them.
The real advantage is height. I stand six foot and can have the lens so I'm not stooped over. This is where the old tripod failed. At full height it was not stable even with a 400mm. This thing is like a rock, it does not move.
Yes,,,its an ugly horrible thing but it runs smooth as silk in every direction (the main rotation has a bearing race inside) and does'nt vibrate at all.
I have not found the bulk of this thing to be any real disadvantage over the last tripod,,it is still something extra to carry and hold.
Carrying the lens with the tripod is not an option for safety's sake but disassembles in less than 4 seconds.
I had to paint the main painted parts green because the "orangey red" seemed to chase the birdies away,,,whether thats my imagination,,I'm not sure.
As ever Colin was right on the nail head about tripods and this lens,,but when I saw the cost of the tripod he suggested,,I needed oxygen,,so this is the result.
The whole rig £14. (annoyingly,,I had to buy the paint,,how cheap is that..lol)