Not wanting to dispute your bed-length issues, though a lot of sleeping issues do come from the after-departure meal with alcohol and coffee. Nice, tastes (usually) good, though not the best circumstances to have a proper sleep, to put it mildly.

Nowadays, I skip the after-departure meal completely and go sleep right away. And have a good 7-8 hours sleep (and depending on the length of the flight some sleeping-in too ).

Eating, I do 3-4-5 hours before departure in the lounge, without alcohol and coffee. And as breakfast, I often ask for the after departure meal with BtC served as breakfast, because the arrivals tend to be around lunch time for my body clock.