I have always had an issue with sleep cycles, even at school it seemed ridiculous to wake up early. The first chance I get no matter how many days I followed an 8pm to 6am sleep schedule I will revert to late mornings.
I think the only time I have ever really felt awake is when I watered and got to sleep from around 4am or later and then wake up at around 2pm.
The world though tends to be on this crazy cycle of early mornings, ontop of that a person goes to work and gets home at 5pm and it will likely be another hour or two before you even get to the things you care to do.
Although currently I can sleep longer, sleeping for 12 hours even is not sustainable ontop of that a person does cycle around to then not being able to sleep much at all.
However looking towards heading back to work and needing to optimize my time after will mostly need to have adjustments come from my sleep.
Before my time off I use to take 2+/- hour naps after a day of wasting time at work then again try to sleep from 4am which gives me at least a 7 hour total on average.
I don't know if there is a better way though, I would think the basic biphasic sleep pattern works well enough since I have at least 1 proper REM sleep cycle.
From the bit on sleep cycles I have seen most push for a solid 8 but I don't think that is realistic for maximum output during the evenings.
It may benefit the day job but in my case I have no reason to feel awake and focused in my day job.
Regardless, I think the biphasic sleep pattern is best but work will need to be done so I can optimize it for evenings while being sufficiently awake during the day for the 8 hours of hell.
I think starting my new cycle when I return to work that maybe a 5 hour after work nap is best which will cause me to only go to bed at around 6am giving me another 3 hours at least.
Personally it will also fall in my optimal work times which are from around 10pm - midnight , you know when you find that sweetspot of being able to focus.
Ontop of that winter is coming and that makes afternoon sleep a lot more viable where as I guess in the Summer I will need to revert to more a midevening nap since the heat at 5pm is still too hot for any proper sleep.
Anyway those are just my musings on my attempts at finding a balance as someone who can easily sleep 12 hours and even then the will to get up is weak.