Your comment spurred me to use a 256GB USB flash drive instead of the WD spinning drive.  256 GB is large enough to do a couple system installs and multi boot them as well as a bit of data backup.    If I need more data backup than 256 GB provides, I can mount a spinning drive or even a network drive and back up to that.

I should have done this a long time ago.  There have been many instances where I've used Live drives when I should have built a maintenance drive.