There is no quality difference between legacy and non-legacy denoisers. The only difference is that the new one is compatible with newer drivers. Yep. I'd mention it in the wiki if they were supported. I answered you here: https://forum.unity.com/threads/bakery-gpu-lightmapper-v1-65-released.536008/page-74#post-5234969 Yes. I was under the impression it's integrated into Unity now, but it seems you need to download the package first. 2019.3 beta I guess?