[question] How to use data that was previously downloaded using "guix pull" in a new system user?

[Rodrigo Morales <rodrigo@morales.pe>]

I'm running guix in Ubuntu 22.04.4 LTS on my desktop computer.

On my desktop computer, I like running experiments just to see what
happens. When I want to run an experiment related to the default
behavior of a tool, I create a new system user (using the command =sudo
useradd --create-home experiment-1=) and execute whatever command I want
to experiment with, this way I make sure that none of my dotfiles change
the default behavior of the tool. On my desktop computer, =rodrigo= is
the user that has all my dotfiles, and the users that I use for running
experiments are called =experiment-1=, =experiment-2=, =experiment-3=
and so on.

I want to run some experiments that involve using the =guix= command.

In Ubuntu, I installed =guix= using =sudo apt install guix=. If I create
a new system user, =guix version= reports the following version:

#+BEGIN_SRC sh
$ guix --version
guix (GNU Guix) 1.3.0
Copyright (C) 2021 the Guix authors
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
#+END_SRC

If I create a new system user and I run =guix pull=. Upon completion of
the command =guix pull=, =guix version= reports the following version:

#+BEGIN_SRC text
$ guix --version
hint: Consider installing the `glibc-locales' package and defining `GUIX_LOCPATH', along these lines:

     guix install glibc-locales
     export GUIX_LOCPATH="$HOME/.guix-profile/lib/locale"

See the "Application Setup" section in the manual, for more info.

guix (GNU Guix) 2b4e3c9847dce02e371ff4dce615789fdfd101fa
Copyright (C) 2024 the Guix authors
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
#+END_SRC

In the experiments that I want to run, I don't want to use the verison
1.3.0 (i.e. the one that is installed through "sudo apt
install"). Instead, I want to use the latest version that exists on my
system. This way, I avoid having to run "guix pull", which requires
significant time (more than 20 minutes on my system). The reason I want
to do this is that when I am running experiments, I very often need to
use a newly created system user.

My question is: In a newly created system user, how to make the =guix=
command be aware of data that has been previously downloaded through
=guix pull=?