One trick I've discovered that makes the custom 3's fit better is bending the memory wire more to the inside. To do this, look at the earpiece from above then align the memory wire along the "line" that marks where the two pieces of the earpiece come together. Then, bend the memory wire slightly to the inside, this will cause it to stay in your ears better and keep the seal.
BTW, thanks to Klipsch for the two pairs of free ear gels! I just got them in the mail, It took around three weeks for them to arrive. But then that's understandable as i'm on the other side of the world.