You can turn an entire industry off in the Trade Advisor, but you cannot mothball individual buildings.

I use a rectangular building block 16 by 5 tiles (inside measurements). This allows pretty much all walkers to go all the way around.

I'm sure you won't go wrong with CA's blocks either.

I think you might need to forget about C4 when playing C3 because it is different in so many ways.

If you PM me I can assist you a little bit.