It's 184 days, not 182 - i.e. half the time. When considering that, remember that INZ count BACKWARDS from the date of application for PR to check this out, which means that, if you're out of the country very often, you need to count your days carefully, checking that they're within the 12 months leading up to submission, then the 12 months before that.
No, if you're going to use the "time in the country" criterion, you don't have to do anything, because the INZ computer records any time that your passport is scanned at the airport, coming and going, so they have all the evidence of that.
I remember that some forum members had a bit of hassle proving separation, so don't take it lightly, and be ready with all evidence you can think of.