How low can I go? 1888HP BWX

[Antripodean]

Just swapping out my Peavey Black Widows - 1888HP BWX - for some more powerful AE TD18H drivers. Swapping to the AEs as they will go better into the midrange.

So now I have a pair of 1888HP BWX to turn into subs. T/S parameters as below:

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| SPLo= 96.39 dB | SPLi= 95.24 dB | SPLi= 96.65 dB|
TSL File Name:PV_BW_18 | üo= 2.74 % | üi= 2.10 % | @ Eg= 2.83 V |
Name : 96000057 BW 1888HP BWX Rem= 6.32 ê, Lem= 2.073 mH @ 1KHz
Model: Speaker- Woofer/ Midrange Rem= 57.68 ê, Lem= 0.724 mH @ 20KHz
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Znom= 8.000 ê Sd= 0.1178 sqM Fi= 33.840 Hz Hvc= 20.7000 mM
Revc= 5.790 ê BL= 23.8283 TM Fo= 36.130 Hz Hag= 7.0000 mM
Krm= 9.948 mê Vas= 230.1325 Litr Qms= 10.947 Xmx= 6.8500 mM
Kxm= 44.661 mH Cms= 116.7856 uM/N Qes= 0.385 Cmx= 2.0000 mM
Erm= 0.738 Mms= 166.1560 Gram Qts= 0.372 Cmo= 5.0000
Exm= 0.649 Mmd= 142.9080 Gram Pmx=1000.000 Wrms évc= 0.2500 C/W
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The frequency range I am looking to cover is 80Hz down to 30hz or lower. I keep seeing these PPSL woofer boxes but I am not really sure how to model them. Also interested in 6th order bandpass. My preference is to use both drivers in the same cabinet. However, foot print needs to be about 500 x 550 x 1000mm (WxDxH). Is there a design I can use to achieve this? The drivers are only 140mm deep.

Appreciate your suggestions