Not really sure on the best way to check it, I'm sure the RST boys will have some input. The ratchet should be self adjusting - try pressing the clutch pedal a few times and seeing if it clicks, or you may feel it adjusting. You can do this whilst stationary.

For what it's worth, I always change the clutch cable when I have a new clutch.

You could get a mate to watch the clutch lever/arm on the box whilst you press the clutch pedal in, and see if it has full travel.

Of course it could also be something else, but nothing springs to mind at the moment.