Imo, predictive astrology is like any other divination or spiritual skill, it takes quite a lot of practice and comes in time. I personally have not heard of any books or websites on it, but perhaps someone else here has.
My main point is a lot of astrologers I'd consider worth the effort to have read use their own natural intuition when reading a chart. This imo includes predictive astrology (future) and looking into current situations people are in and or past circumstances to get to the psychology of it.
Most who practice gifts and are indeed serious are doing it to help others.
General descriptions of what planets are supposed to mean, the aspect meanings and sign meanings imo are not enough.
Imo an astrologer worth their weight should be able to tell the client something even if only a little at first, personal about them. Like if one were to go to any psychic, without the need to ask any questions before hand or foreknowledge. I ask questions when I read- but they are part of the chart reading- and I am attempting to pick up the energy of the chart of the individual, in other words the questions are for feedback, I can not know if my skill is improving, if I give a reading and get no feedback.
In other words, like a medium is expected to communicate with a passed loved one, we do not wish nor want ever for them to fake it. We expect them to pick up on something.
Same for me when I have an astrologer read. I'd expect them to be able to tell me something personal to myself, or situation, present, past, or future.
Many charts I see read are read in the context of you have Sun square Saturn- then a general description of these combined planets that has been memorized.
This is not how I read, and I do not consider it true astrology. This is imo, I do not know how others feel about this.
As to what you are speaking of- predictive astrology, what I know in absolute truth about it is it takes years of practice. Reading charts not only for oneself but also for others, and feedback from others is a must.
I say this because I do not practice astrology in reference to future, I look at the present and past. And that in itself has taken years.
And I am still learning. Always.
Blessings to you, I hope you find more of the answers you are looking for.
Edit: The chart comparisons you speak of wishing to do sound like event charts, where information of the time, place and date of certain events happening is entered and a chart is drawn for that. Could this be what you mean?