I have been giving some further thought as to how I could connect together the three pairs on both spools of cable. Once again, I will define the abbreviations I shall use:
NE -- near end (the outer end of the cable on the spool).
FE -- far end (the inner end of the cable on the spool).
S1 -- spool one.
S2 -- spool two.
B -- blue pair (blue/white stripe & white/blue stripe).
O -- orange pair (orange/white stripe & white/orange stripe).
G -- green pair (green/white stripe & white/green stripe).
LJU2/3A -- Line jack unit with IDCs (secondary).
The third method of connection:
LJU2/3A to NE,S1,B
FE,S1,B to NE,S2,B
FE,S2,B to NE,S1,O
FE,S1,O to NE,S2,O
FE,S2,O to NE,S1,G
FE,S1,G to NE,S2,G
FE,S2,G to LJU2/3A
Of the three methods, I prefer the third because the "direction of travel" of the signal through the spools of cable is always in the same direction.