That is the trick; too tight will cause steering "weirdness" where you are constantly over-correcting, expecially at low speeds....(yes, a technical term! LOL) too loose will facilitate wobbles, etc. and way too loose will cause clunking and damaging the bearings. I've always taken the "eyebrow" comment as an attempt to reinforce that it should take very little pressure to move the bars. The cables make the whole procedure more difficult to set.....removing them would make things easier. When I first did this adjustment, I got it too tight and had to loosen it off again....it really is a very, very fine line.
this is the pertinent bit: You should have to push the bars from one side to the other with the bearing at the proper tightness.
But just barely.
In other words, the bars shouldn't FALL from one side to the other when you give them a slight push. If they do, tighten it some more and try again.