bracing is required. it doesn't have to follow any specific plan, so long as everything is well braced. i've provided one strategy that uses 2x4's.
pl premium would be a good choice for adhesive as it helps fill gaps. air gaps kill performance.
can tuning will be around 28hz or so, so a protective high pass at around 25hz would be required. 2nd order butterworth 12db/oct.
limit power to about 500 watts. constant, full power, sine waves are never a good idea, so use common sense or the driver may be damaged.
a steep low pass filter at around 100hz or so is recommended. 4th order linkwitz riley, 24db/oct.
try to get the driver as close to the top of the cab as possible.
the extra cutouts in the bracing in front of the driver may not be required, but 0.75" would be the safe bet.
gasket tape for the removable hatch will help keep that air tight.
i've checked the numbers several times, but you never know. :-) best bet is to build one and test. if good, go for a second, third, fourth... :-)
should be a fun sub.