Largest tire on stock 18" rims with 2" RC Level?

[RollTide21]

evening y'all, I recently purchased a 2014 Sierra SLT with a 5.3, crew cab, short box, 18" rims, and the Z/71 package. Immediately after purchasing it I removed the stock draft boards and front valance and installed a 2" rough country leveling kit. I am now trying to put some all terrain tires on the truc,k as it came with Pirelli Scorpions in 265/65/18 and I want to have something more aggressive looking and more functional off road. I am trying to see what the largest tire anyone has fit on a truck with similar 18" rims or if anyone has any suggestions. I was deciding between a 285/65/18 and 295/65/18 because I am trying to avoid have any scrubbing while still being able to have 33"s. I am also deathly tired of hearing people suggest nitto ridegrapplers so if anyone has any suggestions other than that they would be much appreciated. 

P.S Will I be able to fit a full size spare under my bed with a 285 or 295?

 

Thanks for any help and Roll Tide!

[flyingfool]

i've seen a few good options on here, try the search bar, i'm curious what you come up with as i got a similar set up.