Now you might be wondering what it looks like underneath? Of course, I'll show you a terrible pic!
Nicely done! Any chance you took a pic of the front after install, or remember how close to flush the top edge of the T-nut was to the front face of the MDF?
(I'd debated something like this when assembling my semi-custom Rythmiks, but since the baffle had a double layer of MDF and I couldn't find "taller" T-nuts - and I wanted to minimize handling for the sake of the gloss black finish - I opted to harden the holes with CA adhesive instead. That turned out to be too much for the supplied screws and several sheared during install. It was agony to extract them and recover, especially as I was trying desperately to protect the finish the entire time. If I ever have to go back in, I'll revert to T-nuts or similar even if I can't find tall ones!)