This happened to me earlier this year. Y eastward, J westward. Since I had way too much to drink during my connecting flights (which were in First) because I was so dreading to sit coach, I passed out before take-off and woke up as they were collecting the breakfast trays.

With that scenario, I didn't mind coach. No hangover either.

Maybe look at it this way. On the departure, odds are that you are going to go to sleep whether in Y or D. Odds are also that you will sleep if seated in biz in either direction. If you sit biz over, you will definitely sleep, but if you return in coach odds are you won't....BUT....if you sit coach over, odds are you will sleep and odds are also good that you will sleep in the biz seat on the return.