The third is right in the middle of labor day weekend. I'm not going anywhere, but that lets preseason week 3 injuries shake out pretty well. Or would people prefer the 27th of August?
Any date / time is fine for me. Also fyi I autodrafted last year, didn't prerank at all IIRC, and I still won the league. Importance of draft is way overrated in casual leagues and most people aren't drafting significantly different than the Yahoo bots or an average draft position would determine for most teams anyway.