By the way, using that Disney WOW Blu-ray A/V Sync chart can be a bit misleading if you are not careful. The brain ANTICIPATES what's supposed to happen and so you can read the chart earlier or later than "reality" depending on how your brain works.
One tip I've found helpful is to go up to the screen with an opaque object to use as a marker -- i just use the remote control. Ignore the flashing yellow dot in the middle of the circle and concentrate on the hash marks around the rim of the circle.
Place your marker one mark beyond "perfect" and focus on THE MARKER -- not on the rotating bar, or the flashing yellow bits, or anything else. While focussing on the marker, LISTEN for the sync tone, and ask yourself, "Did that tone happen BEFORE the sweep arm reached my marker?"
Now do the same thing with the hash mark one step earlier than "perfect" and ask, "Did the tone happen AFTER the sweep arm passed my marker?" The trick again is to focus on the marker, and not try to continuously follow the sweep arm.
If both answers are yes, the sync is in the right region. With practice, you'll be able to focus on the marker and ALSO see the sweep arm reach precisely to "perfect" as the sync tone happens. You can now try halving the region -- that is position the marker half-way between "perfect" and the the next hash mark either side of "perfect" to refine this, but by this point you should be finding it pretty difficult to tell because the interval is so short.
In fact if you are ALREADY having difficulty telling with the first test, train yourself by expanding outwards -- placing the marker at TWO hash marks either side of "perfect". Or even THREE. By that point the answer at each marker should be obvious. Now start pinching back in again, until you can check this over a sufficiently small region either side of "perfect".
This method reduces brain bias because you are forcing yourself to focus on a single location (the marker) and compare the arrival of the sweep arm vs. the tone at THAT location. And by doing this both sides of "perfect" you also force yourself to eliminate the bias your brain wants to insert (the anticipation of the result).