Btw, Jack I've found that the plastic saddles allow you to slide the boat up from the back easier than using the rollers, with the saddles it self centers which it certainly doesn't do with the rollers.

Bill H.

Me too. I had boats try to drive off the side of the rollers when loading, and once loaded, the rollers were much less secure than cradles. On top of that, the rollers left marks on the kayak hulls. I'm not very fastidious, but scrubbing (with polishing compound) those black marks off the boat was tiresome, and some friends weren't happy.
BTW, the rectangular section Thule bars work better for sliding boats through cradles as they resist the tendency of the cradles to tilt forward (rotating around the round Yakima bars).
You need to be careful- not all the Yakima saddles (nowadays?) come with the knockouts to allow fitting to rectangular bars.