Don't get too hung up on the hanging hair test, focus more on the shave test. Your face can tell you the most about the edge out of any of the tests. If you can't get a comfortable edge off of an 8k, buying more or expensive stones will not improve your skills (a common misconception). It's like seeing someone buy a three thousand dollar guitar hoping it will improve their ability to play better. Figure out how to get a comfortable shave off of one stone at a time (starting with the 8k) before moving on.