True Tim, we won't find an answer here.
I believe that a PU that is in shape can move 70 feet from the time after we know the ball is fair (when fielder fields the ball) until the time it has taken the fielder to throw to first, then the runner goes his remaining 80 feet to third. I know I can...
I also believe that a BU can get pulled feet and swipe tags from B or C most of the time (above 90%).
So, by moving up to third on this play, we are compromising a potential problem at first with a swipe tag or pulled foot for, what I believe to be, a better look at a close play at third.
All compromise... no matter how you slice it. You could have situations either way where something doesn't get covered with either mechanic... And like you say, one thread ain't gonna solve the problem that a 2 man system has always had.
But in CT, from my limited 4 year experience
, its general practice that you come out.
And yes, its 127 feet from 1st-3rd. I haven't done math since the 11th grade, who knows where I got 144 from.