Well, I looked at your Astrobin images and you are doing something right. I was going to suggest that if you hadn't added one already, a spreader would add a lot of stability. I know it did for me when I improvised one to test with, so I am currently planning a more refined version. Is that one of your modifications? In theory a pier is always better but if you have modified your tripod and added rigidity, there would be less of a difference.
Given the fact that you are making this with the purpose of being taken down easily, I like your idea of leaving it free for now. You could test with the tripod and if the results are nice enough, you're all set. But if not, your design would make it pretty easy to add the pier later.
I did add a spreader from TPI.
I also fixed the inner legs that had crumbled a little from tightening them too much. First I had a machine shop cut the crumbled part off (about 4") and then I filled the rest of the tube with cement. This helped the tripod a lot it seems. It's heavier now but not by too much, it's still very portable and but now more bottom heavy.
I also had the mating surfaces of the tripod and the head machined, now the mating surfaces are just about perfect.
Edited by PirateMike, 09 May 2019 - 07:36 PM.