I did alot of testing a while back to get a better invis paint than the 0 0 0 0 one.
I came up with this.
255 255 255 1
DIV:Invisible
Inserted at the end of the ColorSet text file in C:\Program Files\Blockland\base\config\server
First off, it makes bricks invisible.
Second, it comes with several advantages over the 0 0 0 0 paint code
1. It spits out a visible white paint cloud so you can see what you're painting
The paint cloud with the other invisible paint was, well, invisible, so this was a good improvement.
2. This paint can be successfully saved and loaded.
The 0 0 0 0 paint code was terribly glitched, and would not load properly when loading a build. This resulted in bricks coming out in the first color of your first palett (red in most cases). Fixing this was pretty much the reason why I looked into it.
With this code however, the paint can is still invisible. Still, it's a minor detail.