New to the forum (obviously) and am looking for opinions and help. I bought the plans for the 15" version, but I have four new 18W6's sitting around. They may not be ideal for this application but I'm hoping they'd at least be acceptable. The T/S numbers are below. I would gladly pay for pro plans. Thanks in advance!

Fs (free-air resonance): 20.0 Hz
Qts (total speaker “Q”): 0.384
Qes (electrical “Q”): 0.402
Qms (mechanical “Q”): 8.740
Vas (equivalent compliance): 9.00    ft3   254.9 liters
Xmax (linear excursion one-way): 0.500   in.    12.7 mm
Efficiency (1W/1m)*: 88.8 dB
Sd (effective piston surface area): 182.6   in2   0.1178m2
Re (DC resistance): 11.04 Ω (in series)
Znom (nominal impedance):  Dual 6 Ω
Pt (continuous thermal power handling): 500 Watts