It's similar to stringing a Gibson style stop bar guitar either the "standard" way (through the stop bar), or "over" the stop bar. The increase in break angle would seem to lower the actual string tension along the fretboard, where stringing over the bar, reducing the break angle, reduces the string tension. The reduction in string tension allows bigger bends. I don't know what the string tension figures are, but you can feel a difference while playing.
But hey, that's only what I've experienced in trying the different methods out on stop tail guitars. My actual preference is to use standard stringing through the stop bar & tune to D.