i've never seen that before...must be fun to watch! nice photo!
... GT2542L fell off Gitzo website......
item #:GT2543L (replaces GT2542L )
Price for the new GT2543L is a lot higher than the B&H price for the GT2542L, plus B&H is including expedited shipping. Nature's way of telling you, now.
I have the Gt2531 (previous version with 3 leg sections) and I find it is quite happy with my 300 F2.8 with or without extenders. If you are not too concerned with the collapsed length then I find the 3 leg section versions to be quicker to set up and a little more rigid. It is not a big difference but it does help.