It looks interesting, although the 'difficulty' field is a bit subjective. You'll probably want to better-define what specifically makes a course a '2' difficulty, for example (e.g. use a rubric or scoring guide), so users of the system can be normed. Also, it doesn't directly take into account a few (in my opinion) important variables. 'Par', for example, is only a rough measurement of the more important hole length and intended number of throws to reach putting range (which is different depending on intended player skill level). It also looks like your rating point increment is directly based off of the 'par' metric.. or roughly what the PDGA does with its Scratch Scoring Average to rating point increment calculation too. What that is only minimally capturing, though, is the scoring spread. Higher SSA (or Par, in your case) is assuming a direct relationship with larger scoring spread, which is not necessarily true. Why not instead actually directly use something derived from the standard deviation of round scores to determine the value of each throw in terms of a rating?