Just something that might make it easier for those experimenting with different field strengths, especially with large or complex fields.
Have an option that allows the painted field within the selected container from x to y without manually repainting the entire field (ie. a container with a painted field strength of 2 can all be changed to levels 1, 3 or 4). Any existing fields of the strength(s) not being changed in that container would not be changed.
Another nice option to see would to be able to change whether the field affects Creeper, AntiCreeper or both without repainting the entire field manually.
that would be interesting...