@sparkymaui , I would save yourself the trouble and find a dealer in Hawaii that Sells Magnepans or better yet Sound Labs. With the exception of subwoofers multiple driver arrays have never worked well, open or closed. The Nearfield Pipe Dreams are the classic example. You can make a speaker that goes very loud but it's response particularly in the bass is going to be very lumpy. It is even difficult to correct then with DSP because the power requirements are so high.
Making a flat panel speaker is child's play. Making a full enclosure is far more complicated. Where open panel speakers work best is with small two way systems comprised of a tweeter and medium sized midrange/midbass driver 6 or 7 inches crossed over to subwoofers at 100 Hz or so. The plates can be made with solid surface material which is much heavier and stiffer than wood. You laminate it to 23/32" plywood making a panel almost 1 1/4" thick. A simple 2nd order crossover and 4 chains to hang the two speakers from the ceiling and you are good to go. Two subwoofers and an active 2 way crossover complete the system. Subwoofers should always be in enclosures. Cancellation effects make open baffle subwoofers virtually unmanageable. People do it but the sound is anything and everything but accurate.