It may take come time but one of us will answer. I sometimes miss a thread but J-rock is dead on as usual.
A large part of information is posted on the decware page. as far as mods thats stuff you have to find it here where the bass heads hangout.
The inside dimesions and ratios I feel are more important than the hieght. also your CC chamber should not be expanded you can slide the baffle ( part the sub is on) into the CC chamber this is the ported chamber. 60 has mentioned adding blocks inside the sealed chamber to decrease volume because you do not want to move the baffle back into the sealed chamber.
The design is best left alone if using a 10 or a 12 although lots of us play around.
Improving on steves design is not a improvement but a trade off of differant characteristics.
you have likely read about using a 4th order model and somewhere in these thread are the inside stock volume that you can work from.
some have dfferant ideas and many times a second opinion is a good thing.. when all of us agree you got something worth doing..
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There is a spell checker but who has time for that.