If you can afford it, Thule Hullavator. They are pricey but trust me if you plan on kayaking a lot, they are worth every cent. You will definitely be able to load that boat by yourself without any fear of scratching or denting your truck. They are rock solid too as I have no drama at all driving at highway speeds with both boats on the truck.
With Hullavators you only need to lift the boat 3 feet or so to get it into the cradles. Once there you strap them in and lift them to the top of the truck. The arms have struts that help carry the weight of the boat.
You can check ebay and save a few bucks that what I did. Note sometimes there are none listed, but if you keep checking sooner or later someone will post one for sale.
Here are some pics of my truck and our yaks. Note these are 15' Ocean Kayaks, one is a Trident 15 and one is a Prowler 15 (basically the same thing). These boats are heavy and this wrack has no problem handling them. Note you will need to get Thule crossbars that are long enough, so the wrack can hold the boat far enough away from the truck. I love them.