Are you taking a look at latitude?
Within this thread, I'm not doing that, until and unless I com across a good text which suggests that latitudes were taken into serious account when judging aspects.
Latitude relates to a position North or South of the ecliptic, which is itself inclined to the Earth's equator. The use of latitude enables us to plot the position of a planet in the same way that we can plot the position of a point on the Earth's surface. Just as two cities can occupy the same longitude on Earth but be 'vertically' separated by a considerable distance, so two planets can occupy the same ecliptic position (by sign and degree) but be vertically separated.
The best example is the Moon and the Sun. At a New Moon the Sun and Moon occupy the same ecliptic degree but that does not put them in the same latitude, if they are in the same latitude as well (which by definition is 0 degrees), then we get a solar eclipse
Virtually all Astrologers treat a solar eclipse as more significant than a New Moon, which illustrates your point about Conjunctions having more significance with latitude.
The same argument can be extended to any two planets sharing the same longitude and latitude, or between planets with the same latitude and ecliptic degree relationships that form an aspect. In practice most Astrologers don't seem to bother much with this, apart from the eclipses, unless they are looking at Primary Directions.That doesn't mean latitude is unimportant (as the lunar example shows) but simply reflects the bulk of practice, rightly or wrongly.
Obviously that's a very brief account and thus is open to quite a few challenges but I don't really want to go into the complexities in this thread because I've no evidence that Hellenistic Astrologers treated it as being of great importance (or indeed of any importance, except for the eclipses).
Edited to add:
By the time of Hellenistic Astrology, Greek scientists had already proved that the world was a sphere and accurately measured it's size and the length of a year. They had the mathematics to carry out accurate measurement of celestial motions. But the practice of Astrologers seems not to have reflected this. They used tables for the placement of planets in the zodiac and these could be out by two degrees or more. So a planet placed at one degree of a sign could easily be in the preceding sign.
Not till Ptolemy was there a mathematics of astronomy that became adopted by Astrologers rather than the reliance on measurements dating back to Babylonian times. This is probably Ptolemy's greatest contribution to Astrology.
See:
http://www.projecthindsight.com/articles/astronomy.html