It may just make more sense to wait until I have enough days after my PR was approved . . .
Waiting makes a lot of sense. Remember to still include the pre-PR days in the presence calculation, but for sure it is a good idea to wait to apply when you have enough days based on well-documented status, which appears likely to be limited to days AFTER the date of landing and becoming a PR. (The easiest way to do this is to do a separate draft presence calculation, not counting pre-PR days at all, and when that draft shows the requirement has been met, plus a bit of a margin, then do the formal, to be submitted version of the presence calculation including the pre-PR days . . . being sure to include responses in the application as to your periods of visitor status.)
The gist of my lengthy posts: If your passport was stamped. Or you had a Visitor's Record. Or your sponsored family class PR application was an INLAND application: To the extent any of these documents YOUR status as a temporary resident, you could rely on those days counting (at the half day credit for each day). Best to still have a bigger than usual margin over the minimum, but it should be safe to rely on pre-PR days for which IRCC is likely to have its own records (in your GCMS records) showing or at least corroborating status (such as the inland sponsored partner application process should).
