I've stalled on build 1920, because the next step I tried, 1922, gave bad results. If you have a working build I suggest sticking with it unless you have specific issues that you know are fixed by a later one. I still want to get copy/paste to Windows 98 working, which is why I tried 1922, but I've decided to stop worrying about it as it's a small thing compared wiith the hassle of updating, trying, failing and falling back.
Re. the old version downloads, I suggest you keep any installer you use, at least until you decide whether you may want to be able to run it again. Old versions are probably available on the Parallels site, but it's way easier to just re-run the one you downloaded before.