Thanks for your comments, when I did this project the Corona Sky with clouds was not available yet if I remember, so the background and windows reflections are a Still Jpeg, but I have used it in more recent works and it really is great for this kind of shots. Regarding the caustics, I've done a lot of RnD to test caustics to see what works, and this setup is a PhoenixFD Ocean Tex as a displacement map and on the UHD Cache I have the Animation preset but with the "Calculate from scratch" and After render "Discard", Render Noise Level at 4% with the Denoising to help clear.