Video.

I'm a stills guy. My knowledge of video is that of reading and instructional videos from questionable sources. First hand practical knowledge may as well be zero.

Video, once and for all I'm committing to learning it. I don't have a huge plan as yet but I figure I have the perfect opportunity to start this coming week. Kayak camping for 9 days solo. I'll be shooting astro on the new moon. I figure the best place to start is by shooting some footage and figure it out as I go. I plan to keep it simple. I'm going to try to do a decent job of documenting my trip as there are many side adventures as well as astro. Possible wildlife, I'm just not expecting much as I'll be on small, somewhat remote island all to myself. I'm hoping for some birding on a day trip to a protected wetland. In my mind I see myself making something along the lines of something you would find on Youtube. My reality is likely unusable crap filling my cards.  I'm going to shoot the paddling portion with the action cam. On dry land I'll use something bigger and shoot the campcraft along with a few other things. One thing I learned is that you need plenty of 'b roll' and I should have no shortage of that around camp. I'll just shoot as much of everything as I can and I'll have plenty to learn from in post. Most likely what doesn't work. My money's on a week's worth of shooting and finishing with a 3 minute clip lol.

As far as shooting goes, I was thinking of shooting in 4k but edit to 1080 which would allow me to zoom and pan in post. I'm taking three bodies and an action cam so I can have a body shooting video any time I want even when I'm shooting stills  with 2 bodies. My question is which body should I be shooting video with? A6500, A7Rii (when not shooting stills, main body for this trip) or the A9ii?

Should I be shooting in a Log profile or something similar? Is there an easy way to tell when it would make sense? My goal here is good solid data for me to start with or it's the proverbial lipstick on a pig come editing time. I will be editing in DaVinci Resolve once I get going.

Is the easy answer to just shoot 4k at the highest bitrate I have available to me? Which then just boils down to card space and how much I can shoot a a given bit rate before they all get full. Since going digital I've never run out of film metaphorically speaking. I fear I will underestimate the card volume required to shoot 4k.