So, I can finally do clean pinch harmonics. For the past while I was only able to get the harmonic by playing the string and then quickly brushing with my thumb, which always produced the fundamental beforehand. However, I've found out how to produce a pinch harmonic from the get go, without having to sound the fundamental first.
The secret was pick grip. After going back to some videos I readjusted my grip, and by exposing far less pick and using more thumb, I can finally get that clean harmonic, consistently! Which makes me very happy.
The problem is I find it quite hard to play riffs with this grip. My fingers/thumbs on the pick are basically brushing off the strings when I play like this. But at the same time it's impossible to switch between pick grips mid song.
Is it just a matter of getting used to and adapting to playing riffs with this kind of grip? Or is there something I'm overlooking?