Wow nice informative thread
I'm currently using calligraphy grip 2 with the thumb going over the pen
ayyThis is my usual pen grip when I'm holding a normal pen and writing
But regarding the different types of pengrips, I do agree that pencil grips allow for more freedom around the tablet, but it's probably more suited for those using large, smooth tablets like Wacom. For small tablets like the Huion, having a small area with calligraphy grip would be more suitable as you literally hit the edge easily if you use pencil grip with a large area. And since Huion tablets tend to have high friction (or my palms are just sticky), you just stick one side of your hand to the tablet and move your pen with your fingers.
Maybe it's just my personal preference.