There’s a thread on E4 about the set here: www.elitefourum.com/t/confirmed-psa-will-recognise-base-2000-update-2021/24039/1 - the later pages include the update about PSA now grading these.
If it makes life a bit easier for you I’m operating a website which aims to improve PSA’s pop report specifically for Pokémon. The ©1999-2000 set has a dedicated page here: pokemetrics.org/sets/18ll-24. Data is only updated there on a weekly basis mind you, so if you’re wanting to log daily updates you’d have to do that yourself.
As for when they started recognising the variant: they started accepting them on 3rd March (as per this email screenshot) the first few cards were graded on the week leading up to Wednesday 17th March.