DAVID: Thank you for the info and links. Apparently the Arca-Swiss is NLA but I'll take a look at the FLM.
JOHN: Thank you. I think I still want a ball head but I'll check out the Gitzo.
PAT: Thank you for replying. I'll look into the Majestic head.
GARY, and ALL: I plan on buying a Korona 5x12. The longest lens will be a Fuji 600-C or (maybe) Nikkor 800 Tele. I'll be using some type of stabilizers on the camera but I need it to safely stay put until I can lock it down for the exposure.
ALL: I should have mentioned that carry weight is a secondary concern. Also, I tried to be cheap and bought a Smith-Victor BH8. It will hold hold a Toyo 810G straight up but slips when I try to vary camera angle more than 20-25 degrees and it's unstable enough that it would worry me to leave it unattended in even the lightest breeze. This is with the knobs very tightly locked down. It would be okay, I think, for a lightweight 5x7 and for just about any 4x5. To be fair though it's only rated for 40 pounds vs. the 121 and 150 pounds of the two David referred to. I just didn't realize I needed to multiply my camera weight by a factor of 8 or 10 for the tripod head weight rating. So-o-o... it looks like I'll be spending more on a head than I anticipated.