SEA-JFK: Lie flat (767) out, C+ back (757) or C+ out (767) recliner F back (757)
 

Flying SEA-JFK, I can only get one direction in F and the other direction C+ within budget. I do not really count on upgrade on this route as DL Gold, but who knows.

Option 1. SEA-JFK on lie flat business 767, return JFK-SEA on 757 in C+.

Option 2. SEA-JFK on C+ 767, return on domestic 757 (recliner) F.

Same price.

Having guaranteed lie flat on 767 in one direction is great, but I still lean towards option 2, because C+ on 767 in very comfortable and there is bigger chance of upgrade on 767 (36 lie flat seats) compared to 757 (20 seats).

I would choose option one with the lie flat going out (especially if it's a redeye). Unless you do a SDC from the non-stop to a connection through LAX, where you'll get D1 service.

As a DL Gold, I would not expect an upgrade on this route. Obviously this depends on time of day and day of the week.

as one who has flown this route 4-5x/year for the past 7 or so years, I concur with OP's logic in the context of the reply ... over the course of the day, the schedules are generally more conducive to LAX/SFO options out of than into JFK

This is the most confusing thread title

I think if you are going to pay for F you should use that to get a flat bed seat and make it worthwhile.

But bulkhead C+ on a 767 is just about as good as recliner first in terms of space. C+ on 757 is not as much of an upgrade.