If you have a long layover maybe you can make the argument for LH F with FCT.
In my book though TATL flights from the East Coast / DTW / ORD are too short to enjoy F. If you stay up for the full meal (to really maximize the experience) you end up with no sleep.
A comfortable J seat that you can sleep on straight away is always my preference (and if you do LH J you can get dinner in the Polaris lounge at ORD first and then just get a night cap and go to sleep).
If you can I'd save the F for the daytime return flight when you can actually maximize the experience.