Help with valve adjustment
 

Alright guys, i have just finished installing my cc503 and 1.6 RRs and i am having some trouble adjusting the valves. I was attempting to do the engine running method and this is what happened. The car started up pretty decently and i was attempting to find zero lash. As this is my first time doing this it is a little difficult. Should you be able to hear the clacking go away with your ear or with a stethescope? The engine is backfiring every once and a while really bad and it seems to be happening at a set interval. I am scared to leave it running for too long because of this backfiring. What would be the most common cause of the backfiring? A valve too tight or too loose?
Also, i am considering going back and adjusting the valves for zero lash with the engine not running using the method on shoeboxs site. Is it still possible to do this? If i go to tight will the lifters pump themselves back up or am i screwed? Thanks for all your help. Oh and i did change the valve springs as well