The "spin the pushrod until it stops" method is poor and subjective at best. I tried it and adjusted it to the point that the valves were always open, however, I could still easily spin the pushrod. Other methods are take up the lash and turn the nut 3/4's of a turn. I've had good success with this method. However, my prefered, but potentially messy and destructive method is to do it with the engine running.
The best way to do it with the engine running is to find an old set of valve covers and cut the tops off. This way you can adjust the valves without the oil splashing all over the place. When adjusting the valves, you can hear it when it's too loose by the clacking noise and too tight by the whooshing noise. Now the caveat. I say potentially destructive as depending on what your piston to valve clearance is, and how far you adjust, you do run the potential of tightening too much and causing contact between the valve and piston. Normally, this is not a problem, but YMMV depending on your cam & piston specs.
Best thing to do is follow what your cam manufacturer has to say.
