Ideally, you want to temp at the same time every day
and after at least 3 consecutive hours of sleep. Obviously that's not always possible, so do your best. There will always be circumstances that can't be avoided.
Whether or not you'll have more accurate temps by temping at the same time or with longer amounts of sleep really depends on your own unique metabolism and body patterns, which will become apparent after you've got a few charts under your belt.
As for which temp to use... if it were me, I'd use the first one. You went to bed at 2am and by 7am, you'd had 5 hours of sleep... which is more than the "rule".
Hope that helps... and Welcome to the Wonderful World of Charting!