displacement question

It's ok to do it, especially for displaced corners in a map.

Generally it doesn't matter what size/ratio your displacement is aslong as it has 4 sides. I would also not recommend making them huge either, as a matter of principle and ease of use.

I've done this before, but later I noticed that if every brush has only one, it's easier if you have to edit them later

Its not a big deal if you make them from 1 brush also. even if you have destroyed a displacement you can easily make that same face a displacement again. There is a [DD] button (displacement drawing). when you click on it all the faces that get removed when making a displacement still show up and you can make a displacement of them again.

I personaly make as much faces of a brush a displacement without overdoing it. It often keeps my map structure easier as i allways vertex edit my brushes to have them perfectly aligned. This means that i dont get any weird faces when i press the [DD] button anyway.

Its just what you prefer to use.