I don't have a brilliant reply but, I might remember you from dirt week? Are you from NM?
I love most things about the YZs...the engine, suspension, quality. But have felt the same as you, they never quite want to handle in corners like a CR. You can move the forks up in the clamps until you get headshake, then back down slightly, sounds like you already tried that. Make sure you have the right front tire and the knobs are sharp. Not like the rear where it rounds off and you still run it for awhile. You could play with tire pressure. In some conditions, I find the lowest pressure you dare before pinch flats works the best. 11 psi-ish? But then if you are jumping and there are sharp edged holes that could be an issue. Also if you are like me, as we get older we get a bit lazy with the body movement...as far as shifting weight forward coming into a corner.