So I'm in the market for a roof rack. Both Thule and Yakima have racks that will fit my truck; the Thule spread is 27" and the Yakima is 30". I know some here have made shorter spreads work, but I'm wondering if there is a big difference in safety/boat protection spending a little more for the 30" Yakima over the 27" Thule racks? Also the Yakima has a 58" wide bar, vs. 50". I guess my question is: what is the optimal spread width for carrying an ocean kayak or two?