I usually set the Ireland locale, they use English but use civilized units. Sometimes there's also a "English (Europe)" or "English (Germany)" locale that works too.

I also use Ireland sometimes for user accounts. For example Hotels.com only offers the local languages when you select which country to use. The Irish version is one of the few that has allows you to buy in Euros in English.

Nowadays this works for many applications. Not for the "legacy" ARM compiler that was definitely invented after Win NT adopted UTF though. It crashes with "English (Germany)". Just whyy.