i just push the gears together and then slowly spin the clutch bell with one finger to feel if theres any resistance, then hold still the other gear the bell is connected to and feel how much movement there is between the teeth, and this has worked perfect for me using the 2-speed on my tyranno. Of course you'll probably need to feel it first when its fitted properly to get an idea of what it shud feel like.
The teeth are all still close to perfect after about 1.5L of fuel.