The configuration used for testing was my own, and can be found at Frontear/dotfiles. To test in much the same way, the following command was used to run 10 isolated benchmarks:
# This was run within the root of my repo.
# To obtain working versions of the other nix* derivatives, use `nix shell` so that there is no overhead in processing the store.
for i in $(seq 1 10); do
time nix eval '.#nixosConfigurations.LAPTOP-3DT4F02.config.system.build.toplevel.drvPath' --no-eval-cache