I have another question or two...

What are the different properties of gypsum plaster and lime plaster? I know lime is superior, but I don't fully understand why, and my inquisitive nature forces me to seek the answer...

Also, does anyone have any experience with clay roof tiles?
As part of the traditional system, I am considering covering my roof with rectangular clay tiles, and was wondering if any of you had any experience using a clay roof. At this point though, I am considering using regular asphalt shingles instead -because they are readily available and look reasonably similar to the rectangular tiles. I know they're not ideal but they will work.