I designed / built mine with a CO2 release integrated
So you have a CO2 extinguisher built into the hood? cool.
And a gas scrubber? even cooler, so whats this in your shed? haha, like it lots, next you need to deck the place out as a clean room and when people come to the door do it in your full biohaz suit!
Your right though, everything to cover up what your doing without looking suss (ie too obvious your hiding someting) is the key, leave no tracks.