Suggestion: Make the factory engineer attack not ending.
Engineers lose this sweet sweet mode when they can´t find any mass or sometimes randomly.
The annoying part is, you have always to watch if there is still mass on the ground, if you are 2 secounds to late
the engenieers go idle and leave the attack mode, despite you would like to send them to another mass.
When they don´t lose the attack mode you can be more relaxed and move the factory attack waypoint just later.
I don´t know if this is an issue, but someone could send some engineers to a location as a weapon and try to eat enemy units,
but this would be probably a very bad deal.