Bias to small, digestible review requests. When possible, try to break down your large refactor into smaller, easier to reason about changes, which can be reviewed in sequence (or better still, orthogonally). When your review request gets bigger than about 400 lines of code, ask yourself if it can be compartmentalized. If everyone is efficient at reviewing code as it is published, there’s no advantage to batching small changes together, and there are distinct disadvantages. The most dangerous outcome of a large review request is that reviewers are unable to sustain focus over many lines, and the code isn’t reviewed well or at all.
This has made code review of big features way more plausible on my current team. Large work is organized into epic branches which have review branches which are individually reviewed. This makes the final merge and review way more tractable.
Your description should tell the story of your change. It should not be an automated list of commits. Instead, you should talk about why you’re making the change, what problem you’re solving, what code you changed, what classes you introduced, how you tested it. The description should tell the reviewers what specific pieces of the change they should take extra care in reviewing.
This is a good start for a style guide ala git commits!