I've done all the reading...I "fixed" my Gen4 19 a few months ago by using a LWD extractor AND a Glockmeister single ss 15# ISMI rsa. It has over 1000 rounds since the modifications with NO failures and NO casings to the face.You are not doing anything wrong do some reading and you will see that glock epic failed on the 9mm gen 4 guns. They have since come out with a replacment spring and ejector that they can install for you just give them a call.
My Gen4 G26 has a polished extractor, modifyed ejector and still throws a few casings to my body, but is much better than before making the modifications. It has 2000 rounds through it...still eratic ejections.