You'll have to figure out the mount because it will be more difficult using the standard WK roof rack. I would imagine it will need to be straight just because of the mounting. As for pattern, the diffused on the sides with spot or flood on the middle is best in my opinion, second best is spot in the middle and flood on the sides. There is a big difference between lights -- if you find a brand, research the hell out of it. Do you have to go with Rigid? No. Should you put your time into seeing what lives up to the Rigid "standard"? Absolutely. Lumens are really up to the bar, again, do your research.
I've said it before and I'll say it again, Google is your friend. Do some research to narrow down your questions then come ask the group.
2005 WK 5.7 ORT | Mod SL (OME struts & 990s) | JBA UCAs & Discos | Saguaro Front Bumper | Warn Zeon 10s | 285/70/17 BFG TA KO | AIRAID CAI | Gibson 3" Exhaust | DiabloSport Intune | JL Stealthbox