Here's a key dish on pinch harmonics. Every guitar is different so when you play a harmonic on a string on one guitar and get a good one it doesn't mean that picking in the same spot on a different guitar will get the same result. Even after I had my guitar set up I had to go through and find the sweet spots again. The sweet spots on a certain string change depending on what fret you're holding down. It's a lot of experimenting and alot to remember if it's a technique you want to use alot.