Many of them I set to dynamically allocate space with the max being 20GB.
But I think the Windows and MacOS ones had mandatory space that was a little higher.
And then if I created them from an .ova or .vmdk they had already been configured for a certain size.
The "real" ones though that I actually use have like 30 or 60gb, and one of them is a copy of a real machine that's like 300gb lol.
And believe it or not I've actually deleted a bunch that I knew I wasn't going to use like a couple Android or RemixOS VM's.