Cool, just curious...why do you want them to be the same everywhere?
NFS?
Or any way of moving files around that doesn't translate UIDs or where translating UIDs is more work; ex. rsync will default to trying to match by user name, but I'm pretty sure tar won't always
NFS, and also just sneakernet. It means you don't have to worry about formatting large external disks with something weird like exFAT.