Recording all those lectures must be a lot of work.   Is is worth while?

My perspective is the new video lectures are much better than my former live lectures. Preparing them has required me to scrutinize the book. Many small improvements were made to it. Breaking lectures into segments averaging 11 minutes duration is a good idea from all points of view.   Giving a formal lecture forces me to understand the material better. That enables me to make the book better. It's even given me new research ideas.

The second year I asked the students about their impression of the book materials versus the video materials. They much prefer the book materials, reading them first, next the video, and occasionally then returning to the book. Does this mean my video preparation is wasted? No. By never lecturing the entire class is discussions. I get to know the students much better. (Another professor finds his students like his video better. But, that simply means they do not like his written material as well.)

In my second year of flipping the class, its size was more than double the previous year (jumped from 4 to 9), but I suspect that not a result of the class flipping, but of my aggressive distribution (free) of newly completed (self-published) book.

Did you have the problem of "students having no questions?"

In the first year I had the problem of most questions coming from two students. The second year I'm taking more control of the classroom to get participation by everyone. I used no quizzes the first year but plan to use about one a week (5-10 minutes) this second year. I have a pile of quizzes for the "no questions" problem, but they were not needed the first year. I haven't yet caught students coming unprepared.

Did students solve problems during class time?

Rarely. Except that I'll be digging out some old quiz questions for that purpose. In the third year the students were pretty good. I printed copies of all chapter exams ahead and had with me in the classroom. From time to time I would pass out an exam and tell them not to put their name on it, upon completion simply compare with their neighbor.

With no lectures, how did you pace the material?

This was a problem the first year. In the beginning I accepted all digressions, but the pacing turned out to be too slow. Making it worse, Fridays were taken up wholly by the lab teacher, and February has two Monday holidays. So I had to accelerate the class --- to students' discomfort. So I prepared a syllabus that spells out the schedule linking labs and book chapters.