posted March 29, 2017 03:39 PM
Maybe because those are more-generalized houses, so they would require the use of a smaller orb?Astro uses Placidus House system as its default. You can change the house system yourself manually. There might even be a way for you to set that as a default for yourself? (not sure)
Placidus is a more-detailed house system (based on 'hours' of time of day). I personally prefer Placidus over the other systems. It's just more accurate for me because I've used it for everything.
You may need that kind of long-term experience with using one system, till you get the hang of 'how' it interprets "for YOU". Don't 'only' go by what the general comments are, or what the books or articles say-- go actually PROVE it, for yourself! You'll feel more Confident about the meanings of your interpretations then. Remember that astrology is not just science, not just art, it's BOTH.
I know that Koch system generally throws the cusps (inside the 4 points) around 5 or 6 degrees in-Advance. This is the preferred house system for some astrologers who use Prediction (Transit) astrology.
For some of those, this system 'seems' to provide more accuracy for predicting, as some planets trigger 'before' while others have their effect AS they pass-over.
You may also want to consider articles on the Weight-values of the planets-- maybe has an effect with certain orbs. (I think Lilly did some work on planet weights.... People who do horary know a lot about those.)
Porphyry (if I remember the article I saw YEARS ago) is good when you need to more generally 'air-chart^ it? -- (do it more quickly 'in your imagination' or head).
IF I am recalling correctly, I had read an account of a student-astrologer who was being tested for his Certifications. Those were the days where astrologers took very stringent tests, in front of a panel of professional peers, to earn levels of Certifications in the field.
He revealed that he was able to answer the question posed, by doing the ^air-chart^.
(Laughing-- don't quote me on that one! I'd have to do the research to fact-check 'where' I read that.)
Here's an article I found (and website) that might be valuable to you.
http://www.skyscript.co.uk/houprob4.html