Lanthum Chloride might be your solution. You still have to go slow, but it is not as expensive nor as time consuming to dose. Dosing a small amount into a filter sock or into the skimmer would get you there eventually.
Having success with higher P levels is a matter of degrees. There are many corals that just do not care at all. I have some that would have stopped growing long ago and would be dead at your levels. Both types are acropora. The stories of people who say that this-or-that high level is OK are indeed having some success, but not same kind as others... and they probably do not care. This is likely why you are seeing some of your 15 get mad, some not care and some in the middle. If you decide not to not worry about your P level, then some of those 15 will not care and you will have weeded out the ones that did not care for your tank.
If your tank is established, then I can save you the trouble... your N is probably between .1 and .5. This is what happens with deep sand beds. Don't let anybody worry you about not having enough Nitrate. First, .1 to .5 is where the ocean is and is not growth limiting. Second, corals will want to get their nitrogen from ammonia and ammonium from the fish waste, so this matters, not the nitrate level. Feed the fish more and the corals will get all the nitrogen that they way, but this adds P as well, so stay on top of your P level.
Once you get the P down a bit, then growing some macro in a fuge might be all that you need. It is growth limited at higher P levels and will not grow as well as if they levels are lower, but it really works if your tank is a good environment for it.