"This is the case with any app that uses OSM. It is a known OSM api problem." 

This is most certainly *not* an OSM problem. Multipolygons add minimal overhead in terms of data size. I was able to download this entire 36(?) hole course, multipolygons and all in 3 seconds. Your software shouldn't be directly accessing the OSM reference database on every hole. What should, and is likely being done, is to cache the data on TGC servers. Any download and rendering problems are with those servers and software and should be addressed with that entity. As I mentioned earlier, many many different people, apps, software, and tools access OSM data and everyone needs to conform to those standards and not map improperly just to satisfy one that is having problems. Gotta fix it at the source of the problem.