For this time, I'm going with:

exporting-server$ guix package -p /path/to/custom/profile -i packages I want
exporting-server$ guix archive -r --export /path/to/custom/profile | xz -c > my.export.xz
[rsync blah]
importing-server$ xz -cd < my.export.xz | guix archive --import
importing-server$ . /gnu/store/blahasldkjf-profile/etc/profile

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