Hi Rob, I'll give you my thoughts on some of your questions.
Robbo81303: 1) If the putting grid shows absolutely no dot movement from all viewing angles, how does one know if the putt will break and, if so, what direction?
Try clicking the 4-way arrow to change the dots to move up-down rather than left-right. Often, when you look at the up-down dot movements, you'll see them move at a slight angle, which means your putt will move at a slight angle as well (i.e. it's not really 100% straight).
Robbo81303: 2) On a 40 ft putt where break is indicated only for the first ten feet of travel, how is it that I achieve a putt with a perfect, unvarying arc throughout the entire distance of the putt?
When a putt like that breaks early, it will continue on that exit angle (the angle at which it's travelling when the break stops) for the duration of the putt. It has nothing to do with your putter's Balance rating.
Robbo81303: 4) Does anyone know why my putt sometimes flies left off the putter face when I miss the ding late, or, conversely, flies right if i miss early?
I think the quick, sharp breaks right at your feet can be caused by 2 things.
One is if there was indeed a sharp break in that direction right at your feet. Those types of breaks are very hard to see sometimes.
The other is if WGT's rendering of your putt travel is not perfect. Once you click or tap to putt. WGT instantly calculates whether your putt will go in the hole or miss, and they try to display your putt travel as accurately as they can. But sometimes, they can't display it perfectly, so what they display is just as close an approximation as they can get. NOTE: I do not know this for a fact, it's just a theory of mine.
Hope this helps.