I hope you haven't invested too much in the app yet. Have these keys been discussed with OSM people anywhere? 

Abbreviations in keys are frowned upon, capital letters are actually undesirable, and I have already mentioned the issue of true/false. Incidentally, app-specific keys are often deleted without comment. Storing information such as lengths and stroke counts for individual holes both on the golf course (here as a list) and for the holes (here as individual values) is undesirable double storage. The former is also difficult for a human to maintain and would mean completely unnecessary additional maintenance. Oh, yes: the standard unit of measurement in OSM is metres, not yards. I cannot guarantee that the list of my concerns outlined above is complete.