Reversing the ascendant

1
Perhaps someone can point me to any research/ideas/references or give their views on this question.

Many, though not most, tropical astrologers reverse signs for southern hemisphere. There seems to be some confusion as to whether all the signs are to be redefined as their opposites, thus reversing MC and IC, or whether the chart is simply mirrored around MC-IC axis. I tend to feel a change should be made, and that everything should be moved to its opposite, but my question is actually only analogous to this problem.

You often read that signs give something of the physical or psychological characteristics of their opposite signs. I find this is often true, sometimes astoundingly so. Does anyone have or know of any ideas as to what criteria might indicate this? My modest research would suggest something involving sect and the phase of the moon (more precisely, as reflected by whether the day/night POF is in oriental or occidental quadrants, calculated as 90? ecliptic sectors from ascendant, ie whether POF is in equal houses 12-11-10-6-5-4 or 3-2-1-9-8-7 respectively).

There may also, it seems to me, be a link with pre-natal epoch. When the a pre-natal epoch conception chart is highly plausible (reliability of birth time and good knowledge of length of pregancy), the PN moon seems usually to be on the natal ascendant when that best describes the person, and on the descendant when the reverse is true. But I may be imagining things, as the PN chart is not really designed to be completely rotated 180?, and the southern hemisphere analogy may be better.

Many thanks for any pointers or ideas.
Graham