What you tune it to has to do with how much series resistance there is and the desired room/speaker placement, though some folks ignore these and tune them to a more personal taste, such as the 'West Coast Sound' championed by Altec, and now apparently by Iconic. Great party/DJ alignment, but no good for a more accurate reproduction in a typical wide BW HI-FI app of today.

One thing for sure though is that such a large vent you propose will have strong enough pipe harmonics that will audibly comb filter with the driver's response above ~250 Hz if not damped.

GM