Wayne Parham Messages: 18787 Registered: January 2001
Illuminati (33rd Degree)
Pocket holes for screws are fine. I've always seen them as a high-quality construction method. Not really needed for loudspeakers, but certainly they don't cause any problems. The screws are really only there to provide clamping force for the glue anyway.
As long as the panels are true, the glue will make a good seal and you don't need anything extra like silicon caulk. That's only necessary on really sloppy builds.