Newbie needs measurement help

I've built several simple circuits to get my feet wet and learn the ropes ... schematic reading, soldering, basic design, etc. I am now about to embark on building the NP Zen amp, but before I begin I want to have all the info I need.

Perhaps this is a ridiculously basic question, but how exactly do you go about adjusting for symmetrical clipping? I have access to an oscilloscope and function generator, but have been unable to locate any good references for basic measurement techniques (proper hookup, what to lookfor, etc.). If anyone could provide guidance or direct me to some good reference sources (online or print) I would greatly appreciate it.

It's visual...put a test signal into the amp and turn it up until it clips (the tops & bottoms of the sine will look like somebody cut 'em off with a knife), as seen on an oscilloscope. Then adjust until the clipping is the same on the positive and negative swings, i.e. symmetrical. Nothing to it, as long as you've got a 'scope and a freq. generator.
There ain't no such thing as a dumb question, as long as the intent is serious.