In all seriousness, mounting a spare tire on the roof is not a good idea. A 285 weighs what? 100lbs?
Mounting it up there raises your center of gravity, it becomes a projectile in an accident, it could add to getting hung up on low limbs on the trail. It makes your MPG worse (not that it matters much with these trucks). It's a PITA to get up and down from there. It's just not preferable.
If you were on a long excursion and needed more than one spare, go ahead...mount a 2nd or 3rd tire on the roof...just don't do off camber stuff.
If you're worried about the hinges, they can be replaced. They also have swingaway tire carriers that are nice...expensive but nice.
Just take a look around and look at the tires mounted on roofs...maybe the occasional kid with a Jeep XJ (I was guilty of this back in the day). There's a reason people don't do it.
If you insist on mounting a spare on the roof, get a good rack that mounts to the gutter rails, grab a quadratec cherokee/grand cherokee magazine, and go nuts.
But, please don't.