Depends on the amplifier you want to use. Some amps don't like the 3.5Ω minimum impedance that parallel wiring would produce. Other are fine with that and would typically produce much more power into that load than into a 14Ω series load. If you have a surplus of power, then series would give the amp more control over the speaker resonance at 31Hz, since the damping factor would be about 4X higher. This would affect the sound audibly (it would reduce output at fs), so I guess the best answer is to try both and see which way sounds better.
Some dipole designs use the driver's resonance at fs to extend bass reach and increase output at the bottom of the passband, so if this is the intention of the designer, a series hookup would thwart that.
