The Yakima #6 Landing Pads (specifically developed for mounting on fiberglass rooftops such as the Jeep Wrangler hardtop, fiberglass pickup truck camper shells, toppers and caps etc). You want to be sure to get 2 pairs of the Yakima #6 Landing Pads (set of 4 total) which permanently mount to the Wrangler Hard Top roof (just follow the easy instructions that come with the Yakima #6 Landing Pads). You then connect the Yakima Control Towers and pair of Yakima round cross bars to the Landing Pads. You'll want to make sure you go for the 58 inch cross bar length, as this crossbar size will allow enough room to haul 2 kayaks at the same time. My personal favorite for the kayak racks is the Yakima Mako saddles / HullyRoller kayak carrier combination. This way you have kayak rollers on the rear crossbar that you can use to easily slide the kayak up and into place on the kayak rack. Be sure to get two pairs of the Yakima Mako Saddles and two pairs of the Yakima Hullyrollers for transporting 2 kayaks on your Jeep Wrangler hard top. You might want to also check out these
Jeep rack photos or these
Jeep roof rack pictures for more possible alternatives and resources for a Jeep kayak rack system.