FT: tugs and firing arcs

A ship is towing a pod into battle (i.e., a "battle tug").  Are both
the ship and pod portrayed as one unit or as two separate units?
This affects targeting, firing sequence, plotting (although I think
that one plot affects both), critical systems, threshold checks,
hull layout.  The modular Sparrowhawk design from SFB gave me
some ideas for ship designs but I'm not sure how it should be
implemented in the game.  Using the towing rules I can gain
10% space for items.
Example: an 80 mass ship "tows" a 100 mass object.  Using
average hull and main drive 4 the combined 180 mass ship has
10 more mass available for systems than a regular 180 mass ship.

Can a target be in two arcs at the same time if it happens to
be exactly on line between the two arcs?

Glen