thx for the reply!
not sure why you linked this. it does not help answer my question.
thx. i know how use bind-dirs because, as you said, i “rtfm” 
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to clarify, what i asked was “where is the most optimal place to put custom folder icons?” and is it the same place in a template (fedora or debian/whonix) as in an appvm to make them persistent?
this is a qubes specific question (answer below).
using bind-dirs is not necessary since “In an app qube all of the file system comes from the template except /home , /usr/local , and /rw.”
so, ~/.local/share/icons is a persistent place to place the custom folder icons and so is /usr/share/icons.
the answer as i have come to understand it is…
if you want the custom icons to be available system-wide for all users and/or install them in a template so they will carry over to appvms based on that template, then place the folder icons in
/usr/share/iconsif you only have one user account, or just want to install the custom folder icons for one appvm, then place them in
~/.local/share/iconsand they will remain persistent.
hope this helps someone
ava
ps. @xn0px90 cheers! thx for replying and for offering further help via dm.