For me, everything that comes with Poser install, goes into the main Poser runtime.

With few exceptions, everything else goes into one of the external ones.

The exceptions:

• Materials (not pose file materials....material room materials)
• Python Scripts
• !DAZ  foldes (just a copy of each one. The original is left in the external runtime)
• Copies of other morph folders that get deposited into the top level of "Libraries" where the !DAZ folder is.
• V4 (For some dumb reason they only install to the main Poser folder.  S I then copy the files to my external runtime)
• M4 (again, I make a copy and put them into my external runtime)

Personally I find that I really don't use the installed content from Poser. I really don't even remember what all is in there from Poser 6, Poser 5 and the legacy stuff from earlier.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi