I have started a new page on this blog here (it's also on the little toolbar above), where I plan to detail how we tweaked each Sonlight core to make it secular. I've only added a couple of cores so far, but I plan to write up B and D soon, since we are using those now. I will add future cores to the page as we use them. Sonlight cores are quite easy to make secular. Oftentimes, we even end up using some of the "religious books" because they have good information in them. When we chose to do that, I will note it on the list.
.I love the Sonlight program and really think it can be used by anyone, regardless of religion and personal beliefs...it just needs a little tweaking, which is the point of the list. I hope someone finds it helpful!