The dominant planet in a chart?

1
Hi, I've been reading up on traditional methods of astrology lately....but I've hit a slight stumbling block...how do I find out the dominant planet? And by dominant I mean that planet that has the absolute most to say about the native. I'll use my chart as an example of this confusion:

I am a Pisces Rising. My Ascendant is at 27 degrees of Pisces. Jupiter rules my 1st house, he is in domicile in Sagittarius and in the 9th.

At the same time, I have the Moon in the first house, in Aries 8 degrees from the Ascendant.

From what I've read, planets in houses are more immediate and influential than planets ruling houses. So that would mean that the Moon being in the 1st house, near the Ascendant would have more to say about my personality and life than Jupiter, right?

Please tell me what you think!

2
In general, Guido Bonatti says that the dominant planet indicating one's physical self is the ruler of the Ascendant, while the Moon and Mercury indicate the soul, so their rulers are also dominant planet. The difficulty arises when he says that one should seek out the almuten of these places. This is difficult because the definition of the almuten or al-mubtazz can be a matter of controversy.

If you look at the ruler of the Ascendant and the dispositor of Moon and Mercury, however, you will be well on your way to identifying some of the most important factors.

3
Very broadly speaking modern astrology tends to use everything in the chart to describe part of the native's personality. Traditional astrology concentrated more on the external; there is some overlap. Modern astrology is not limited to the personality any more than traditional astrology is limited to external events. It's the emphasis that differs (and the techniques). In traditional astrology the planet that has the most to say about the native is the ruler of the ASC or in some traditions the almutem. This may or may not be the strongest planet in the chart. It could be the weakest. There are weak people.

The concept of the Lord of the Gentiture could be closest to what you're looking for and like a lot of concepts in traditional astrology, there is more than one way to determine it. One is to find the almutem of the ASC degree. Another, more subjective, is to find the planet that has the most essential dignity that can act, usually a strong planet in an angle or succedent house, if there is one in the chart.

Ptolemy did it this way: He called it looking for the quality of the soul. Soul was a different concept in his day than it is today. Others call it significator of the manners.
1) A planet in the first house and in the same sign as the ASC*. If there are two use the one closest. If two are close use them both. If none then ...
2) Any planet or planets that make an aspect to both Mercury and the Moon. Tight orbs only.** If none then ...
3) The planet or planets that most engage Mercury AND the Moon. This one is the most common and the most difficult to grasp. "Engaged" is a broad term. You have to look for things like rulerships, mutual receptions, next aspect, last aspect, dignities etc. It takes some practice. And there are usually two planets that fit the bill. Note: Ptolemy does not use the lights as significator of the manners. Mercury is OK. Morin chastised Ptolemy for this and approved the use of the lights. Your choice.
4) If none of the above works, then use the ruler of the ASC.

Look at Tetrabiblos Book III Chapter 13 for full details. Ptolemy gives delineations and in my view at least it is this chapter where he is at his best. Lilly also discusses this in Christian Astrology.

*Ptolemy does not mention quadrant houses. Therefore he does not discuss the possibility of having a planet in the ASC in a sign other than the ASC. For this reason we limit the use of an occupant of the first house to one in the same sign even if 29 degrees rises and there is a planet at one degree of the next sign. I wouldn't use a planet in the same sign as the ASC that was far from the ASC degree. But that's me.

** The doctrine of the tighter the aspect the greater the influence is pretty much universally accepted. If we are getting into the nitty gritty of the native, then we want tight orbs of only 3-4 degrees maximum. Yes this is arbitrary and under certain conditions a little bit more than 4 might be acceptable, but 5 or more is getting pretty far away for something like this.