Largest 20" tire for '13 2500HD on Bilstein 5100's

[eppyfish]

Hey folks,

Been on the forum a while, but just got into a 2013 Silveardo 2500HD duramax.  Been looking around trying to confirm max tire sizing and I'm not sure I've got it cleared up.  I'm trying to see if I can get a 35x12.5x20 on a 20x10 -19 to -24 range with minimal lift.  The truck's got a set of bilstein 5100's so there's that minimal lift.  I'm glad to do the NorCal mod on the front fender to allow the angle when turning.  Any first hand insight from anyone running 35's with less than a 2.5" or 3" lift?  Maybe a 295/60/20 instead of the 35/12.5/20.  Really wanting more than a 33.  Appreciate any advice you guys have.  Thanks