No smart Bluetooth stylus is perfect right now.
And with 3rd party smart Bluetooth stylii, there is always a learning curve.
You have to play with the wrist/palm orientation settings, sometimes.
AND the big thing is to always put your palm down on the screen before drawing or writing and keep it on the screen while you are actually DOING any writing or drawing.
If the Adonit script didn't work well for you on your iPad Air 2, I would recommend the newer Adonit Pixel.
It's is designed from the ground up to work acrosss a very wide range all almost ALL existing iPad models EXCEPT the iPad 2 (2nd generation).
I use one of these with my own iPad Pro and, using it properly and with the listed compatible apps, works really, really well.
See the Adonit Pixel here.
http://www.adonit.net/jot/pixel/
If you decide to purchase, to make sure you are getting Adonit's lastest stylus and stylus firmware, only order/purchase from the Adonit website and NO other online locations!
Good Luck to You!