Every sub is different, you can not generalize small box = this and large box = that. IF you want to be specific get a box program like Bass Box and use the real T/S parameters of the woofer with something like a Woofer Tester from PE. Only then will you have designed the absolute right box for that driver.
The right tools make all the difference and they cost money. Till then, use what the manufactures recommend, they have these programs.....
As for taking up space with additional wood. It is done all the time to adjust for testing of subs. See how each reacts to changes.
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95 Contour SE '01 3L