I found the armoury units to be useless, and gave up capturing the armoury structures.
The troops you save by not capturing the armouries are much more of a benefit than the 2.5x strength troops the armouries build.
It's possible to fire your character's pistol even faster. If you quickly alternate between clicking the mouse, and the mouse button on a laptop with the built-in fingerpad and mouse buttons; you get a double-tap-like effect.