We had wind today! Steady 15mph with gusts to 35mph. So I trudged out to the reservoir with the three travel tripods above. The problem, as always with the X2D, is checking focus. There's no practical way to guarantee that you nailed it. So I trusted the little green square, as it was always overlapping the edge of a distant building. OTOH, with a 1000x filter needed for 1 or 2 second exposures, AF may struggle. Well, that's what I did. Buildings, as usual, 2 miles away.
Conclusion - the RRS was sharp one out of 4 times. The PD and Heipi were never sharp. This was extended to eye level, which was the criterion mentioned above. I didn't lug the big Gitzos out there, as three travel tripods weigh more than a Gitzo Giant. All images with XCD 135mm + 1.7x. I refocused at least every other shot.
First, the no ND filter crop. f/9.5 1/230 sec
The next three are the best of 8, four 1 second exposures at f/5.6 and four 2 second exposures at f/8 for each tripod.
The Peak Design
The Heipi with my defective ballhead replaced with an Arca Swiss L60 leveler
(There is a *very* slight possibility that I mixed up the PD and Heipi results. I had the impression of more camera movement with the PD. I don't think anyone would be happy with either.)
And the RRS 1
Better, but not great.
Moral, I think, is that if there is wind and you're shooting a long-ish lens, these travel pods will REALLY not do the job. Shooting ultrawide? Probably fine.
If I get motivated to try this again, I'll do all my focusing with the ND filter off. It's just a pain to go back and forth. (Not really, I'm just a bad equipment tester.)