2-man Mechanics, run-down situation

[WestMichBlue]

No outs, R1 on 3B, R2 on 1B, you are BU in "C."

R2 stealing on the pitch; F2 throws to F4 inside 2B, R1 is holding about 5' off 3B. R2 stops and returns towards 1B. R1 still holding, so F4 throws to F3; R2 starts back and now we have a run-down developing.

1 - PU has to maintain position for a possible play at home so he cannot come down the line to take the 1B end of the play. Should PU move to 1st base side, maybe 15' up line? From that position should he make a tag call, or just observe to backup the BU?

2 - Should you, the BU, move to the 2B end of the play? Or move more to the center to make a call at either end of the play. If BU moves to center, is he possibly in the way of a throw should R1 break for home?

WMB