JD - how are you? Sorry been running around the OP chasing steel
PR is fun. There aren't too many bones but the ones that are there are big. Quality not quantity.
The island of Culebra has some tucked-away bonefish spots I really enjoy and am thinking of going back there even there there are many more productive spots to choose from. With a few more trips to work out the mysteries of the place I am pretty sure I could be consistent hooking 8 pound + bones every day. Places with lots of small bones can be fun but there is a certain funkiness about this little town that is charming. There are also huge permit there.
PR main island has lots of tarpon, but most of the areas are inaccessible without a boat or a guide. The only population that is regularly fished is the huge resident group in the San Juan lagoon system. It was all I could do to hook one about 40# on a fly, but they eat live pilchards every cast as the guide Pete hired was bent on showing us every 10 minutes.
There are both open ocean tarpon and resident tarpon on PR. Open ocean tarpon are move around for two reasons - to follow bait, and to spawn. I don't think anyone knows much about the spawning migration there (compared to the Keys for instance) and the pilchard swarms are unpredictable. You basically need to know someone who lived there to know when it's happening.
Residents probably inhabit every lagoon on the entire island but you need a boat to get into them. You will find residents at any fish cleaning dock on the island and if you are not at a tourist trap who wants them around to draw crowds no one cares if you hook them. In fact the locals will laugh at you for even trying
Any more specific tarpon info will have to be off-line. When are you going? I am thinking early March (?).