Max advisable TKC80 tire size on a Scrambler?

Hello all, first post here. Just picked up a pretty green and silver '08 Scrambler this past weekend. Nice low mileage bike overall, pretty psyched about getting it on the road. But it needs tires. I want to eventually build this bike into a desert sled, so I'm thinking I should go with a set of Continental TKC80 Twinduros on my Scrambler.

On the rear, from what I've read, a 150 will fit on the back of a scrambler. But some say even though it may fit, it screws up the handling to the point where it's not worth it. 140 seems to be the upper limit from what some say. Others say they run 150's with no trouble. I'm planning on building a desert sled bike, not for really riding offroad, more for visual purposes. I don't really care that much about the bike being a GSXer corner carver, although I don't want it to handle like crap either.

Same goes for the front. Any advice on the biggest practical tire to run which looks good, but doesn't screw the handling up horribly. Again, doesn't need to provide sport bike handling. And I assume there will be an adjustment period riding with these big chunky tires and getting used to how the bike is managed. I'm adaptable and don't mind that. But I also don't want to be stuck with an unrideable or unsafe bike if you know what I mean.

Thanks in advance for any advice or anecdotal experiences.