A project came up where I'll have to do some green screen + video compositing in after effects/premier. This is not a subject I have experience with yet... Would anyone be able to share some resources on how I could learn this more in detail?
Thanks in advance!
Nick, I only partially answered your question in my long post.
I don't think you would have to mess about with different sizes, for the simple reason that you are not exporting anything and the pages in DR are fully linked. So you would use the original frames in Fusion at full size, then use optimized media/proxies in the Edit page, back to full for the Color page. But completely without having to render it out.
I don't know enough yet, but I imagine it is possible that one might prefer to render a shot that had a lot of VFX just to make things as smooth as possible. DR does have a Render in Place command, which I imagine allows one to make a ProRes422 clip. Not tried that yet.