If I kept mine with an open bed, I'd put on a sturdy contractor rack with round bars and kayak saddles or good minicell blocks on those. No issues from sliding a kayak on from the rear with no roof in the way. I would love to be able to stand in the bed to strap the boat in, which this arrangement allows.
But since I can't do without a topper, I got mine with tracks that accommodate Yakima Landing Pads and Towers. The tracks allow adjustment of the crossbar spread, if desired. The Landing Pad and Tower system's advantage lies in the fact that you only need set the cradle or saddle tilt one time. After that, the click-in feature retains whatever angle you set. Bars and towers are very easy to remove and install, and if you leave them on you can lock the system with the optional cylinder lock.
I only rarely rooftop because I prefer trailering. But having a rooftop rack does come in handy sometimes.
Recreational Kayak Paddle
Pull-Up Strap Handle Kit
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