Just want to add to this thread that I bought a Sirui K-40X ball head about a month ago. I've had a lot of ball heads over the years and this one is absolutely brilliant and the best I've ever owned.
I haven't been able to fault it so far, not a featherweight married to a Manfrotto 055XPROB, so I'm glad I'm not a photo hiker.

Holds the Nikkor 70-200mm and the Nikkor 200-500mm with ease and not the slightest of movements.

The Sirui K-40X is nice and big for big gruff hands