Dirtnut, not sure if your tractor has rear hydraulic remotes, but if so, wouldn't a cylinder operated assembly on the rear wheels of your grader be sweet??? That would allow more vertical blade movement and would give better blade control.
I too run a grader, JD770D, it has a 241" wheelbase (measured from front axle to center of rear tandem drive) with the 14' blade forward of center at 101" from front axle. On a grader the blade is located as far to the rear as it can be and still allow complete 360 degree blade rotation and give the operator maximum blade visibility. If located rear of center both of those would suffer dramatically.
Overall, blade control and effect would have probably also been maximized with your table centered on the beam. Would have also increased your blade vertical control. Good job on the build though, appears to be bullet proof!!!
A modern grader is a mechanical marvel to watch. It has the ability to offset front wheel side draft by utilizing the rear steer and placing the rear tandems toward the tow side of the angled blade. I can take a full cut of hard pack soil without sliding the front tires sideways.
With an overall machine length of 375" it has a turning radius of 276". Pretty amazing that it will turn in a circle smaller than it's length!!! For it's size it is an amazingly manueverable piece of equipment.
Here's a picture of my new baby!!! Ain't she cute!!!