Hello, I am thinking about building one of these: Mike Ralph's DIY Iso Box And putting a 2x12 with G12K100s in it for testing. I need to be able to play loud in order to test out tube amps at full power, but not bother the neighbors. Any issues with the isolation cabinet design I should be aware of? I basically just need to make sure the tone sounds OK when the amp is running full bore. I was gonna put an SM58 inside the box and run that into a PA and then either use a headphones out from the PA or listen to it on monitors at a lower volume level. What would be good dimensions for the length of the box? (I was going to make the width and height slightly larger than the 2x12) Any issues you can think of I need to be aware of with an isolation box? Thanks!!