I had a lot of problems there with the Jett saddle. It was definitely the right width in the rear, because the narrower one didn't support my sit bones. But it was too wide (and too tall on the sides) in the middle. I switched to the Ruby, and things have been a lot better (well, now I'm having chafing towards the front, but that's either the shorts getting slightly loose on me or from how the saddle broke in--there's a big dip now). However, the Ruby is a race style saddle, and so I wouldn't really recommend it for really long touring rides. Still, you may need a saddle that is wide in the back but tapers more towards the front, or is at least not as tall and squishy on the sides as the Jett. It was hard for me to find the right saddle, because a lot of ones with a good taper in there aren't wide enough at the sit bones. If you think you could do without a cutout, I think that may make it easier. You could try Brooks or Fizik.

Like the others said, if your shorts are a little loose in the chamois, any chafing tendencies will be magnified.