Surface area will be the main (but not necessarily the only) determining factor WHEN all other considerations are at optimum. And that's the rub. If you split up the woofer locations or have less than ideal enclosures for a given sub, then you may be going backwards as you increase overall surface area.
Always start with the best singular location/exposure/orientation first and the max enclosure displacement second. That will dictate the best loading method (sealed, ported,etc.) and the best woofer for this particualr application.
Something else worth noting...All woofers of a similar size and construction will have roughly the same amount of total bass energy. However, the design focus in each case will determine where and how you get that energy. The exact same goes for the enclosure design.
While I've not answered your question with an overly-simple, non-substantive response, I have given you a sequential process that will serve your goals better. Start with the boat.