Could work - certainly won't be able to use the second cooking grate though. And it could be a delicate balancing act to keep it from slipping and falling into the coals (as it was designed to sit one way - right side up).
Since it seems obvious you wouldn't be using the bottom grate anyway, if just clearing the coals is all you want (and you don't necessarily care about water in the pan), I recommend using a clay saucer. Just drop it on the lower grate. Much easier solution and it gets you the clearance you need.
Or for cooks where you'll need both grates, buy the smaller Brinkmann pan.