Although I followed the sizing recommendations well, I thought, I realized pretty soon after receiving my device several months ago (a Mature Metal Jailbird) that the cage was longer than it needed to be. The base ring and the gap were fine. Since it was very comfortable, a bit of extra space in the cage didn't seem important at first. But I realized it had a decisive effect on how the device sat in a pair of trousers. As it was, the length was a little greater than the length from my body to the middle seam in the crotch. As a result, it had to go either right or left. This had the effect of moving the base ring in the opposite direction and angling it slightly, and of making a visible bulge when I sat down. So I spent a considerable sum to get a replacement one that is an inch or so shorter. The result is wonderful. I no longer have the feeling of being shoved to one side or another, and there is no more visible bulge. I thought it was comfortable before but now it's even better. I also find it more comfortable for overnight wear. So let me add mine to the many accounts I've read here of the benefits of erring on the small size when deciding the dimensions of a cage.