I have the stock size spare and I have 33's. Im making an educated guess that my best bet is to use it on the front axle, so if I blow a back tire then Ill have to do some swapping. This is to protect the limited slip out back...is this correct? Would it be safe to use the donut 245 on the front with a 285/65/18 on the other side?

http://www.dieselplace.com/forum/showthread.php?t=182783&highlight=spare+tire

Here is a link to a discussion on spare tires. I recently changed tires and wheels and went with a spare the same size as the tires I run.