I think that smaller, more frequent PRs are generally preferred. I know I prefer to work that way. However, as long as the PR is isolated to one particular change and does not contain several unrelated changes, there shouldn't be a problem.
One thing should be said, though - we are very particular about code quality, and we strive for consistency between different parts of code. Sometimes it may take an iteration or two to get the PR up to our standards.
As long as CI passes, you have met most of the requirements - but occasionally there will be code review comments which may seem like nitpicking. You'll get used to it - we do the exact same thing to ourselves too. :-)
In general, don't worry - we are a friendly bunch. If you're ever unsure about anything, find us on Zulip and we can discuss any plans you have.
Regards!