About Dorico 2 sound libraries

I see in the Download assistant Playback 1 and Playback 2 libraries. What relation do these have to the libraries I have currently installed from Dorico 1.x? I’m saving space right now but I assume I can download them later in the assistant, but, will it be possible to download them to a separate location (e.g., external HD)?

If you’re upgrading from Dorico 1, you can just download and install Playback 1 (which will update HSSE2 to HSSE3) but not bother at all with Playback 2.

If we went hog wild and installed everything, are there sound files we don’t need and can delete?

No, nothing will have been duplicated.