I just re-read your opening post, Greg g1r2e3g4.
I don't think I addressed your question, sorry.
If you are mounting only one boat on a trailer then all you need is the crossbar spacing (that's the 67") and get'em on the same centerline.
The "lip" you refer to goes to the rear for both cradles. I position our boats so the front cradle just touches the front of the drivewell opening. Or, the rear cradle sits just under the rubber handles on the amas.
For all my griping about Hobie, the cradles are really great (even if they are asymetrical). They make launching and pulling out a breeze. With the new trailer, tower and box, set-up or break-down takes us on average about ten minutes for both boats. And that's with us working at a leasurely pace. It means that if we want to go out in the evening for an hour or so we can and it's no big hassle.