I always struggle with photon mapped caustics - which is why I rarely use them. I have a setup I’m testing and the results are shown below. First is the RGB pass, the other is the Caustics pass. Settings are posted as well. There is only 1 light generating caustics, it’s a standard spot focused tightly around the subject, and it’s set to 7000 subdivisions.
You can see the caustics look mushy/soft in the render, and they are obviously blotchy in the Caustics pass - but the settings are very high adn the caustics map is nearly 1GB. If I want to get crisper and cleaner caustics this is going to go through the roof.
Anyone have a tip for which parameters to adjust, and how much, for another test? I have been playing quite a bit, but at 30minutes a pop I only have so much time… Direction would be much appreciated 
/b