I’m glad to hear that UA's routing rules are quite generous in this regard. How can I review the specifics of this generosity? (Can I review the specific list of airports that will work for the 23-hour layover trick on a United award to Europe?). Thanks for the clarification!

Also, on United miles, it seem that their website gives an error every time I try to add a layover segment. I would like to make sure the options are still 100,000 points before calling in. How can I review various online options without calling in?

Thanks again!