Here's another tutorial if Greg's didn't answer your question > http://motorbicycling.com/showthread.php?t=22726
You said, "I have the cable as loose as it wants to go". That sounds like your problem. The clutch cable should never really be 'loose'.
As long as the engine idles well don't worry about the throttle slide position. 1/4" sounds like a lot but as long as the idle speed isn't too hight, don't worry.