I didn't find the gravity feed idea worked that well ... so pumping is best ... BUT ...
The clutch pedal doesn't return when you floor it with the bleed valve open. So you have to pull it back up by hand (or foot) as there is no fluid pressure or spring to do this for you. But when you do that you suck back the dirty fluid as it isn't a one-way valve either.
So the best method, if you haven't got an eezibleed, is for one to be in the car to push the pedal down and pull it back up and another to pull the pipe out and push it back in between each pump.
So basically, after fitting a suitable bleed pipe and catch can to the clutch slave:
1) lift up the circlip so the feed pipe can pull out a small amount (it will stop unless the circlip is pulled out too far)
2) pull out pipe until it stops
3) push down the pedal
4) push the feedpipe back in but don't push the circlip down .. this closes the bleed hole and stops old fluid going back up the bleed pipe
5) pull up the pedal by hand
return to step 2 and follow to 5 until all the dirty fluid or air bubbles are cleared.
Then while the pedal is held down, push back the feedpipe and replace the circlip.
Lift up the pedal and check for leaks
During steps 2 to 5 ... the guy under the bonnet also checks the fluid level in the reservoir and tops up as needed.
Done this twice now and works fine ... and if you are careful you can do it alone*** ... next time though I will probably shell out for an eezibleed kit!
*** keeps you fit as you run back and forth from drivers seat/door to bonnet! Not recommended if you are doing this on a public road with neighbours watching