So I think the opposite. As I said above, a few books a season would be perfect. The first few books are far too small to sustain an entire season. Later on things get harder as the books get bigger.
But I agree that the episodes would probably need to be around an hour at least to do things justice.
I don't actually think we disagree much...
What I want would be fulfilled by doing 3-4 mini-series in the first year, one for Storm Front, one for Fool Moon, one for Grave Peril, and maybe one for Summer Knight... each of those being 2-3 hours of entertainment broken down into episodes of whatever length works best for that part of the story... (20-90 minutes per episode (literally, episode 1 might be 40 minutes while episode 2 is 20 and episode 3 is 53 minutes)). I would call Mini-Series 1 "Season 1" and "Storm Front" and while I would release 3-4 books in one year for the first year I personally wouldn't connect those together into a season, though I wouldn't object to naming them Mini-Series (or Series) and connecting them together.
Having Season 1, Series 1, Episode 1 be a 67 minute episode and the first half of Storm Front, while Season 1, Series 1, Episode 2 is a 71 minutes and the rest of Storm Front, while Season 1, Series 2, Episode 1 is a 53 minute episode and the first third of Fool Moon, S1s2e2 is 48 minutes and S1s2e3 is 69 minutes and together they wrap up Fool Moon... and so on (Grave Peril being 3 more episodes of season 3 making up series 3, while Summer Knight is 4 episodes of S1s4) would for example I think make us both happy...
I would drop the season designations from those as confusing and use the word season for series and not reset the mini-series numbering between 'seasons'...
I would also be happy with S1E1a, S1E1b, S1E2a, S1E2b, S1E2c, S1E3a and so on replacing the designations listed above. I would be happier if S2E5a were the first part of Death Masks (and S2 didn't have E1-E4 at all) under this naming convention, but I wouldn't push too hard for it... (it would be so different from anything else)
My Preference would be to get 3-4 2-4 episode seasons in the first year, and 1-3 3-6 episode seasons per year there after as it keeps the numbering clean between the books and show (book 5 is season 5 and comes out in year 2).
Long story short, I think we both agree on how much content (minutes) each book should take and how long (in years) it should take to get to each book... we just prefer to name them with slightly different schemes.