AFAIK, I've always seen it recommended that V4 should be installed directly into the main
runtime.  Why, I don't know.  If I"m wrong, I hope somebody else will say so.

I'm wondering about the external runtimes too.  I see an "Add Library" button, but not an
"Add Runtime" button.   Do you see an "Add Runtime" button?

Let the explorations begin.  :)