Thanks for the nice words on the 3D model! I'm also working on one of the LaBianca house but not all of the floor plan is known. And I have a pretty decent model of Barker Ranch, too. I've been given some info on Spahn but haven't touched it yet.
Here are some renderings from the Cielo model:
http://www.charliemanson.com/temp-cielo-renderings.htm
I didn't model the cars myself. I just downloaded them elsewhere and they aren't quite the correct vehicles, but close enough for now. For those obsessed with tiny details, notice the blue lighting near the cars in the night "photo." According to the floor plan shown in "Helter Skelter" there was a blue light there.