Coming back to the hole in the wall, so it would be more efficient for making the edge to have a single brush with more points to do something like this:
_
/
_/_/ ___| |
rather than have multiple cubes like this:
_
/|
_/_/ | ___| || | | | |
I hope you can make out what I'm trying to explain.
Also is there a way to add more points to a brush after it's been created? Thanks again