03 GMC K1500... 4" Lift tire Question

[FastChev]

Got an 03 GMC K1500 that is getting a 4" Rough Country NTD lift next month. What is the largest tire I could fit? I dont mind some trimming. I want something bigger than 33s. I have 33x11.5s on it now with no rubbing (stock offest 18s and slight T-bar crank). I'm looking at some Nitto 295/70/18s and some -12mm offest XD wheels (has to be at least -12mm offset per Rough Country)

Thanks for the input!