dvdscar,"Knowing Eric, the rule will be "No, the TV series will not establish canon....except for when it does."
He reads minds...
Print and visual story-telling are two very different undertakings. What typically happens when a book is turned into a movie or (especially) a TV series is that the visual version of the story becomes essentially -- I can't resist -- an alternate history of the original story. Much will be in common but some things will change. In and of itself, that's fine. If I were writing the script for 1632 _I_ would change some aspects of the story. Things that work well in a printed medium won't always work well in a visual medium, and vice versa. What you hope is simply that the visual version of the story is done well on its own terms.
As far as the issue of "canon" is concerned, I think it's a moot point. Let's assume for the moment that:
a) A TV series is produced.
b) It is successful enough to turn into a multi-season project.
c) Each season is based on one of the so-called "mainstream" novels -- which, for the record, are 1632, 1633, 1634: THE BALTIC WAR, 1635: THE EASTERN FRONT, 1636: THE SAXON UPRISING and my next solo novel scheduled for publication in January 2016 whose current working title is 1636: A WORLD OF HURT.
d) That will require six -- count 'em -- six years, beginning no sooner than two or three years from now.
Okay. By that point -- let's call it the year 2022 -- the number of novels published in the series, assuming we maintain our current pace, will have increased by at least a dozen. Of those, at least three will be mainstream novels.
My point is that there's simply no way a TV series could catch up with the print series unless the TV series lasts as long as Gunsmoke or the Simpsons, which is highly unlikely. That means it will always be the print series that's establishing canon.