Hello Jan I know that you are busy but would you consider making a couple of shortcuts that go like this,
a shortcut that makes the selected color on the stecil palette the active color for stencil( for example if green is selected this shortcut will make everything with marching ants that is the same color.)
send selected to brush container
If you cannot do these I understand you are a busy kind of guy.They would just help me in my work flow. Thank you for what you have done so far.