Pete, Great work! Truly great! I am amazed that you did a 9x3 without an indexing head. I have one I built from Manfrotto parts, but greatly improved on some of their machined components. I tried a few multi-row shots by hand and gave up and went to an indexing pan head. I use the head for pans, but also for large format outdoor shots like 7x6 frames and more. The way you did the HDRs is the only way I've found possible. Stitching distortions are not the same from image to image, so the HDRs must be combined before stitching. I typically do 30 to 40% overlap, especially for images that lack detail or contrast.

A lot of my shots are waterfalls here in Tennessee, and the falls, like your ocean, lack synchronized points for the software to lock onto, so I have to do occasional hand stitching, although PTgui does work better than any other software I've tried. I often have a lot of very close foreground, so my camera and pan head are calibrated for precise rotation around the exit pupil.

Like you, I have had great results with Genuine Fractals for taking large pans and making them larger. The results never cease to amaze me.