regarding bltlength of same spec and same dia of blt and different number of bolts

For a 1.125 dia bolt I would expect to have

BDIA 28.58
XTRA 6.35  (Equivalent to 2 screw threads [8 threads/inch   25.4 / 8 x 2 = 6.35] )
BITL 28.9   (1 x Nut Length)

For a 1.125 dia bolt I would expect to have

BDIA 28.58
XTRA 6.35  (Equivalent to 2 screw threads [8 threads/inch   25.4 / 8 x 2 = 6.35] )
BITL 28.9   (1 x Nut Length)