For the validity rollups report, I was time-boxed, I had four months to produce the report. I already had a lot of background knowledge on the subject, so I wasn't starting from zero, which helped. The time was split about 2.5 months on research and 1.5 months on writing/editing. I had a rough idea ahead of time how much time I wanted to devote to writing/editing and made sure that my research schedule did not cut into that. That's usually how my process goes when I am time-boxed: have a deadline, estimate time needed for writing/editing, and the balance is time for research.

Generally speaking what I do is I research and think until I think I understand something well enough to write about it and then I write about it. Sometimes the writing takes several iterations as I work through my thoughts. During the research process I also do a lot of learning/thinking "in public", mainly on Twitter, which helps me refine my thoughts as other people give feedback or share more info.