Great work Graham and team, I'll be switching to it on OSX.
I wonder if you took a look at some of the modifications done by portable-nix (https://github.com/DavHau/nix-portable), most important ones being:
a) Allowing user to choose the location of the nix folder (for example $HOME/.nix) by using bwrap or proot
b) Same binary for Win/Linux/OSX on x86_64 (Also see https://ahgamut.github.io/2022/07/27/ape-rust-example/)
And then, somewhat unrelated: c) Can it be used within NixOS as nix.package = ?