I wonder if these are used in Horary readings, or not.
If they are, what are their priorities in making judgements?
Any reference source for these in Horary?
Note: these descriptions are based on my personal practice and are not entirely in accordance with traditional authors, since I don't follow the same philosophy.
With that being said, I mostly use just POF (part of fortune) and POS (part of spirit) in horary.
POF indicates querent's "outer world", circumstances HAPPENING TO HIM. It indicates querent's money and possessions as well as querent's body and health when relevant in questions. It indicates good fortune, success and luck (or lack of it) happening to the querent. You get general picture of this by looking at POF's dispositor but it is really aspect of relevant significator to POF itself that is strong indication.
POS indicates querent's "inner world", querent's state of mind, his inner nature. When the situation is such that querent has a choice, a decision to make, it indicates which way this decision may go. In general, it indicates ACTIONS INITIATED BY THE QUERENT, as opposed to POF and circumstances happening to him. It also indicates querent's reactions (inner impressions) to circumstances (through indication of his state of mind).
Both POF and POS are really two sides of the same coin, just as "inner" and "outer" world are inseparable.