So I installed an old 500gb Seagate 7200rpm drive in the optical bay of my 2011 15" MBP using the NewmodeUS caddy without the bezel. As expected, there really wasn't a good way to secure it. After removing the bezel, the part of the caddy facing the disc slot on the case is bare metal. I found that I could reinstall the screw closest to the slot opening that held the ODD in, in such a way that the shoulder of the screw would grab the caddy and hold it somewhat securely. I've since ordered a 1tb WD Scorpio Blue to go in it's place, and I've been pondering some additional methods of securing the caddy so as to avoid movement and reduce vibration. I'm thinking that a foam/rubber shim under the Wifi card bracket would do nicely as I could use the Wifi bracket to hold down the caddy. I didn't measure it, but I'm thinking the gap between the bracket and caddy is about 4mm. Anyone else come up with methods for securing it a little better?