Thinking through this again, I wonder what the likelihood of successfully connecting in BOS would be? At this point my options coming back from Europe are:

1) EU - LHR - BOS on BA J // 1:36 minutes // BOS-DTW on B6 Y

2) EU - HEL - ORD on AY J // 2-3+ hour connection // ORD-DTW on UA Y

I've already paid to reserve a seat on the LHR-BOS (sunk cost fallacy) and I'm apprehensive about Finnair's "AirLounge" seat and inflight catering... On the other hand, the AY lounge in HEL should be nicer than the BA Galleries, but I won't have access to the platinum wing...