Adding lightning protection is a smart move. If you're still hunting for info, I have a suggestion. I think you should try using MCBs.For your setup, it's best to add the lightning surge protector to your main DB. This will provide the broadest protection for your whole system. A 40 kA surge protector is a good choice, offering solid protection for most residential setups.Since you're using a three-phase 63A system with a dedicated line for your HiFi den, you definitely want to ensure that line is protected. The other two phases covering your pool, pond, and other stuff should be protected as well.