Act 1

Act 2
I think I gave you everything in act 1.
I believe that the 0.7mm and 0.9mm were unused when I started. You could use this info to also figure out how long of a line you could write with one full piece of lead.

Act 3
I don't really have anything for you here. My calculations seemed kind of strange and I'd really be interested to know if others have tried this. There might be some complications such as: did I apply the same amount of pressure for each of the pencils and for every line? was I careful to make sure that the lead was extended out far enough every time I drew a line? (I think so.) could the angle that I hold the pencil affect how long it lasts?
If what I saw was real, this is a pretty cool problem as the results are not linear. You might be able to determine a sweet spot for best lead thickness. Of course, I just like thick lead because it doesn't break as easily.