Nice reasoning seabreeze - I was like you with my earnest obnoxiousness lol, trying to help people "see".
Wasn't there also a line of reasoning from Daniel 9:27 about gift offerings to cease at the half of the year. The times being mentioned there was 7 years. and apparently, it had a greater application in the death of Jesus at which time there would be no more need for gift offerings. That also would place his birth in the fall/autumn.