I had the yakima saddle mounts for a prior yak. They didnt work very well at all for the pa12. Then I saw Tom Kirkmans post on the "Pro Angler Tandem Trailer" using pvc, and for $6 made the perfect roof rack for my pa12.... slides on and off like a dream, conforms to the hull troughs, doesn't deform the hull, it's cheap, and easy to install. I used the yakima straps to attach to the cross-bars on my xterra; but I also installed pvc tubes in similar fashion but simply bolted on between 2 short saw horses for a perfect place to store or work on the pa12. I loosely placed them on the bars, put the boat on top (with some help) to "position" the tubes where they want to go, and marked the location. Then removed the boat and attached the tubes in the exact same location so they will ride perfectly in the troughs. Of course you could simply measure, then measure again, the mark and have at it I suppose
Loading/unloading isnt so bad. There's a you tube video on it. Wheel the rear of the boat at an angle to a few feet behind the vehicle. Place bath carpet on the car. Lift the front of the boat (1/2 the weight) up and lean it on the carpet on the top of the car centered between the tubes. Let the tires fall out. Now lift the back half of the boat (1/2 the weight) up and push - the boat slides easily over the tubes. Reverse the process to unload, except insert wheels and lock 'em in place after you lower the back of the boat to the ground and before you lower the front end of the boat. Took a little to get used too but now I do it quite quickly and easily; and I'm not a young strong dude by any stretch of the imagination. I actually find it less stressful than it was lifting my sport on and off the top of my xterra since I couldnt simply lean, lift and push/pull that boat on and off the car...it was simply to short for that so I had to lift it's entire weight - which wasnt too bad, but still was more than this method with the pa.
Here's a pic of the rack on my xterra. Ignore the dent on the front of my roof - that was actually made, if you can believe it, not by one of these big boats but rather by my i9...it was so unexpectedly light the 1st time I threw it I up there it shot up to high and came down way to hard, and the hard plastic ribbing on the bottom dented my car...doh!
http://i1265.photobucket.com/albums/jj516/stevelibs/IMG_0388.jpg