Great idea on the port. Stacked and glued sounds like the way to go!

Cups on the front? Unusual, I know. I had to work around my neighbor's schedule, and while I was waiting to do the cutouts and rebates on the baffles, I assembled the remaining sides, caulked the inside seams, added fiberglass, and coated all exterior surfaces with primer and then black top coats. Having the cups on the baffles enabled me to transport just the baffles when hole cutting day arrived. It's a minor compromise for me - function takes priority over form some times, and that's OK with me!