Don, We used 30,000 miles per person, for the one segment, over water, upgrade, redeeming United miles.

We found we need to book connecting flights through LHR with lots of time in between. The last flight we had connected through LHR, we had two hours time to do so. Because of distance and the crowds coming in for World Cup, as well as going through security again, we just made it onto our connecting flight! If it were me, I wouldn't even consider a 45 minute connection.

We like Frankfurt airport and it's less hassle. As I had said, if you can upgrade with Lufthansa, do it. Their Business class was superb the last time we flew with them.