Question about shooting arch and Overlap shooting

[Ludwig]

An ug of average tribal loose order bow armed infantry which is 4 elements wide (identified as s1s2s3s4) is shooting at an enemy unit  (identified as x1x2x3x4)
s2s3s4 are 4 base withs away from x1x2x3 shooting directly ahead
My Questions are: Does s1 get to bow shoot at x1 as an overlap calculating the range through s2???
or Does s1 get to shoot at x1 if only 1 front corner of that element is within 4 base withs (that would be the front corner of s1 that touches s2 on the side
or does s1 NOT get to fire at all because Rule Book 9.6 Shooting page 91 B. Target Priorities 5 "Otherwise most toops have a 1BW arc of fire.....
I'm unclear about arc of fire.....Thanks
                                                                                                                                                                                               

                                                                                                                                                         s1s2s3s4
                                                                                                                                                             x1x2x3x4

[nikgaukroger]

Ranges are measured from the actual shooting file.