Hi,
Regarding time it takes to do Starting Points: it varies a bit. My son wasn't super motivated in the beginning (he was 12 at the time) and it being the beginning of the school-year, well, you know how that is! It probably takes up to 2 hours a day at this point but I have my son working on the literature aspect, the bible/worldview aspect and the history section concurrently.
The syllabus is set up so that each of the sections are worked through one at a time, but I wanted my son to have more history, and to go through the theology a bit more slowly. This has worked pretty well. Right now he is reading Mere Christianity, Frankenstein, and working through the history book. He also has Biology, Grammar and Comp, Latin and a hefty music period but he is keeping up.
There is a yahoo group for Starting Points as well as Worldviews of the Western World so you could also get more feedback there. I have personally learned a lot Starting Points and Worldviews about where we are as a culture and how we got here. The downfall is there is no teacher's manual, as in, there is no answer key. Also in answer to your question about discussion time, it varies. We mostly discuss when ds is having difficulty understanding what he is reading. Wish we did a better job at this but...
Barb