To be fair, no mine isn't the best fabrication job, it's something I salvaged out of a project I attempted years ago so it still has the obvious signs of my inexperience with the mill at the time. Regardless, it mounts similar to most aftermarket ones I've seen, with a stepped slot and socket-headed cap screws, which will always have a little bit of wiggle room to throw the sight mounted to it off by that much. Hence why I suggest an integrated rail or at least one built to match with either a dowel or keyway for guaranteed alignment.
As for the CO2 knob, mine is grease, in fact it was greased already when it showed up at my door. And while Lelands are ok, and that's what I use, I just happened to use a teammate's el-cheapo 12g the other day at practice and it was a royal PITA to seal.
I'm not saying these are huge flaws or reasons not to buy, but I figured the whole point of us getting the "prototypes" is to find what works and what doesn't work so well and report back so CCM can improve their product. Those are the two biggest things I've found to suggest so far, everything else has been pretty flawless.