I have a 2015 GMC Sierra 1500 with a leveling kit. I am keeping the stock rims with are 20x9 “snowflake” wheels. I was originally going to get new wheels 20x10 and put 33x12.5’s. What I am looking to know is what is the max tire size that I can put on my stock rims and would I need spacers and any idea what size? Any and all help would be much appreciated.