So, there were 3 tractors pulling a planter (one in the middle, and one on each end) ??

If so, that sounds  r e a l   smart  .....How would one go about "hitching" a tractor to the wing of a planter?

If the 3 tractors did not pull the planter in exact time, you could screw up a planter in a hurry !!

A 120 ft. planter.....the thought of it alone kind of scares me...My sprayer doesn't even have a 120 ft. boom !!

I shudder to think what a 120 ft. planter would cost...I also shudder to think what it's gonna cost to "un-tweak"/un-spring it.  Years ago, a neighbor borrowed a plow from my Granddad.  The neighbor hung a corner post with the plow, and sprung the plow pretty bad.  The neighbor said "Don't worry, I can fix it".  My Granddad said "Nope, you can't un-spring a plow".  The guy tried, but it couldn't be done...this was with a simple plow, somewhere in the 16 foot (width) range (this was years ago, when equipment was "small"). 

If the planter is really sprung, I doubt it will ever be like it was originally.  I'm sure the tolerances are pretty tight when it comes to the folding, and all the workings of the unit.