Thanks for the advice John, Malcolm. Will it be sufficient to get a Gimbal head for the 055x legs? Say a 393 Manfrotto?
The 055x legs seem quite stable to me, but I have not used anything else, so my impression is not relative to something else.
If the plan is to lurk low and shoot, is there a suitable non-extending tripod that would do the job?
I used to have a Manfrotto 393 until I tried a Wimberley 2 - sold the 393 straight away to a friend who sold it on as soon as he found a Jobu Gimbal for sale. I think you get the picture, the 393 is OK and is MUCH cheaper than the alternatives, however having owned both there is no comparison in actual use.
I have also owned the Manfrotto 55 and again it's great for the price but doen not compare to my 2 series Gitzo let alone my 3 series. Will it hold up the 500 - yeas easily, will it be steady and damp vibration well - no but then it is not designed for these lenses.
As a side note I use a Gitzo 3320BS for low level work - it is rated at 18 kilos but will support 105 kilos (ME!) and is ridiculously rigid.
I don't understand spending that much on a top quality lens and then skimping on necessary accessories - still that's just me! As I mentioned in an earlier post you can have a look at the used market where I bought an excellent tripod & head for 300 GBP.