Time outside class - Figuring how to Flip

So as I reflect on how we are going to do homework in the coming school year, It's 2013 shouldn't HS HW look different, I am really trying to figure out how to use a flipped classroom to help deliver content.  I know there is value in doing practice and problem solving during class when I can help guide the students.  I also know a lot of the low level practice can be done outside of the class.  But how much is enough?  What I mean is how much time besides the 220 in-class minutes do I need per week? 

In the past I have asked for 15-20 minutes of outside work 5 days per week, for projects, homework, etc.  - though students tend to procrastinate the projects into 2-3 hour sprints.  And it should be noted that I had already taken daily practice to 4-8 problems that are complete review for practice (I don't assign new content for homework).  So my thought going forward is to keep the 100 minutes per week of outside time (with study halls that is not too much), somewhat tough to pick a number because everyone works at different speeds, but it is a target.

That would allow me to assign about 20-30 minutes of "online" practice per week, 15 minutes of pencil/paper homework per week, 25-40 minutes of project work per week leaving 15-40 minutes for flipped instruction.  That would be about 2-3 videos per week (seems like a lot).  My goal would be 1 video per week, perhaps 2.

The problem is how do you know whether a student watched the video, it would be awfully hard to do practice in class without an idea of the content (students will try to though - asking to be taught the video info in class).  How do you know they watched?  Reflections (google docs)? Notes?  A worked sample problem?  And what do you do with the students who don't watch the videos, is it the same problem as homework?   Remember most students are minimalists, at 16 who cares if you understand, they are just trying to get it done (at least that was how I was).

Currently I make students stay after school to do the work on the same day (see HW FAQ), I treat assigned work like deadline work in the world, and I suppose I could do the same with flipped videos but I still need something to check (a problem, note sheet, reflection, a quiz).  My temptation is to do notes for upper level courses and perhaps a google doc reflection in the trilogy courses (Alg 1, Geom, Alg 2).  I plan to start making some Physics videos soon -- that would be a high level course in my school.  So I would expect to see notes (because the course is open note for all quizzes, tests and exams).  In the trilogy courses I think I will start with the google doc reflection (thanks to Brian Steffen). 

Either way the commitment is made -- math is gonna be different.