Hi
Mark, the process of course rating/sloping is too exacting to go into here, with all sorts of plus/minuses (hole by hole that is) for features, terrain, hazards, sizes, tee boxes, location of penalty, grades of slopes, etc...it has only a coincidental connection with par.
Player's particular handicaps come from the relationship of one's running average scores against the aforementioned slope/rating, not par.
Handicapping/Re-handicapping individual holes (in which I've personally participated for a handful of courses) starts off scientifically and then is (traditionally) balanced anecdotally for each nine of the course - - vis a vis you don't want "shot" holes in any one cluster or weighted to any one side of the course.
The process starts by taking a survey of 700-1200 scorecards and seeks to measure the differential between what a "scratch" player scores on any hole, and what an "18" handicap scores on a hole, and then allots the handicap strokes to where the "18" handicap needs them most... after those results are surmised, then the handicap committee eyeballs where the "truth" of the survey lies and then makes the closest apportionment between the nines.
The latter part of the process, however, is usually where the human element comes in, and committees (who are only given guidelines, not official mandates) then "stroke" their courses as they see fit, with apportionment among the 9 holes "sides" and seeking to avoid a cluster of potential "shot" holes in a row.
cheers
vk