Great thread, I just finished building a larger version of this using the equivalent of the CP3 Tubs 22" x 16 " x 6 ½". Learned the hard way, don't try and use 2x1's for a spacer, not quite thin enough, i've got to go back and glue in some plywood strips now , other than that turned out great. Now the real test is if it stands up to the 300 ASF's I just tossed in it.