First off the coil 6-1 if for the injector system only.It's not for the tube cells.
The bidirectional winding means that you would wind from left to right and then back left again,and so on until you get the amount of turns you want.
Unidirectional would be from left to right only, or right to left.
Longitudinal would be from left to right or right to left,just like the longitudinal lines for the earth.
The stainless wire is for the 6-1 coil only.And the copper wire is for the rest.
The vic coils for the resonance cell was all cooper,all five coils,and they were all the same gauge wire, 29 gauge.
I seen one 6-1 coil,but it was wrapped in paper,and you couldn't tell what was under it.
Don