running a short piece like that is going to act more like a light bulb than a speaker wire.I don't get how you arrive at this conclusion. Again, 12 inches of 18 gauge wire adds a net of 0.006 ohms of additional resistance to the signal.
Also, light bulb filament is a mere 46 micrometers - it doesn't even rate on the AWG scale, the smallest gauge being 38AWG (100 micrometers).
Care to explain the science behind your declaration?