I'm not one of those people who stresses about hitting that 8 hour target though. I mean, I have no reason to doubt the research that shows what it shows about that target, but I also don't think stressing about it is going to do me much good. That in mind, I generally follow the idea that if I'm tired, I should go to bed even if it seems like a ridiculous early time, and that if I'm not tired, I can stay up and do more, even if doing so means I won't get a full eight hours.
I can say that I have a pretty similar approach. I try to be in bed at time to complete at least 7h30 hours of sleep... since I have "alarm clock" for working time compromisses, like you pointed out. But I can say that fairly I fell more or less rested when I wake up. Off course that are some particular days that I feel that I could rest couple of more minutes, and I try to compensate going to bed earlier the next evening, even that it is "awkwardly early for a ground up"... 😅
Couple of weeks ago, I summed up some fatigue during the week, and in the weekend, I manage to sleep for 9h plus hours! That I find the "perfect way" to communicate with my body. Not having the compromisse to "hit" the 8 hour sleep time everyday, but "listening" to my body and respect his needs.
I can say that when I have the will to cut off caffeine for more then two weeks, my sleep quality and duration increases undoubtedly. Recently I made a 5 months period without caffeine in any form (beverage, pills, etc), and I felt great! But I had to return to the magic beverage due to some extra work that I was dealing with. Let's see if I can implement another long period "off caffeine".. Fingers crossed!
Have a great week!
Oh, good luck getting over caffeine again! It is a very useful drug, but the fact that it's do difficult to then wean off of makes it tough.