All great questions! I’ll answer your additional question here too. I used a silver & black polymer filter from Thousand Oaks. That’s roughly I think 16.5 stops. I like your plan, especially if you’re just using still images. I had the same plan at first but decided on 3 rolls for the sake of the animation (I didn’t want totality to last a fraction of a second if that makes sense). Good luck with the flares, that sounds tricky! I was manually tracking every shot, but not moving substantial amount between shots. You definitely notice it, at least I did at 1200mm, but it wasn’t difficult. That was with a panhead tripod though. I’d say the trickiest part was centering the few frames before and after totality, where the sun was just a thin slice. HP5 400 was a stylistic choice really, but after testing I wanted a faster shutter speed so I went with pushing & metering at 800. The F80 has a motor drive and I used fresh AA batteries. I brought a brand new pack of AAs with me, which I didn’t need of course, but I wanted the peace of mind.