whoops... doggone it '55, I missed your post again
Ok... I'll bite, but I'm pretty sure you're plenty hip to the right boom shut off and just wanna 'compare notes' so to speak.. and for the sake of others who are not aggies or might not be savvy, I'll share my take on it.
But first I guess I better apologize to Meat Servo

It wasn't my intention to sound critical, just really curious... after all, we all know that the 'paint' never really paints a
real picture of how the spray laid down, and by that same token, I don't believe that a still photo is every really a good qualifier of what was really going on compared to the live action...
Anyways... back to the
right boom shut off that's
right for us Pratt and normal turning Garret drivers because we take advantage of the props slip stream which helps ensure that there is no vortices at the belly. For those backwards turning G's, it
should be left shut off...
Right boom shut off has nothing to do with chemical savings (rate), and everything to do with drift control...
If you look at the pictures you can see the wing tip vorticie, and you can see that under the center it just stops cold. With a well patterned right boom shut off you can literally park your nose on a row, and be assured that is where you're spray is gonna stop. No drift from the offending vortex, because there isn't one...
Looking at Meat Servos first right boom shut off pic shows this well (except IMHO the wind
appears to be such that it would have worked out fine with or without the right side off... but that's just an opinion garnered from a still photo

)
Ok... moving on to pic two... in this pic it would only make sense that he is trying not to drift across the road... but in that case his drift control (the nose of the airplane) is on the
wrong side of his spray... in other words, if he's really trying not to drift across the road, and that is why his right boom is shut off, then he needs to be flying the other way...
Clear as mud?
BTW, I have laid 'hot' herbicide mixes down like this with paintbrush accuracy... and it still surprises me to go back to the field and see just how crisp the line is where the boom ends
Take care, Rob