i thought with the pinch test that it would stall imediately if the tune was lean? If it's reving up considerably for 3-4 sec then it will still be a bit rich....
The revs should increase slightly for no more than 2 sec and you on good tune...
These days, i tune to the idle. Once the idle gap is set, adjust the mixture accordingly. If it idles high, it's slighty lean. If it idles low, it's slightly rich....
This will only work when you get the idle gap right, as you can get a false lean if the gap is too big.....