A346 on Frankfurt-Boston is a nice uplift in F capacity combined with the A380 on MUC-BOS. Direct boarding from the lounge via Gate E10 and the (admittedly small) dedicated F section of the lounge make it a decent route for Eastbound F, although I personally prefer Westbound in F and Eastbound in J, because you just don’t get the full First inflight experience on an overnight flight, or ground experience on a flight departing the US.