Seeing as how you won't make HON, I say go for SEN and 1K. You have 2 years to make and requal for SEN, and if you're buying full fare Y on UA, then you'll be able to take advantage of the 150% EQMs on full fare and the upgrades with no instruments (but not confirmable in advanced).

I believe LH also sells some decent enough BOS/NYC-Asia D fares, which would yield a ton of miles and keep you on LH metal.

You might want to check on participation of LH and UA in *A upgrades. I don't think UA does anymore, but if LH does, its a nice way to upgrade to F on TPacs (NH especially).