Any six lug original equipment will fit your truck from 1988 to 2008. the six lug from 1988 to 1999 was intended for a 4wd and 5 lug for 2wd. Back spacing will be the same for 2 and X XXXXX XXXXX Chevy trucks ( Silverados, Tahoes, and Sububans). If you have not picked out a set of wheels, you can check with your local Chevy dealer for a good deal on brand new take-offs.
You can install up to 20 inch wheels, but the 16 & 17 inch wheel wheels will give you the best ride, and try to stay with a factory size tire to keep the tires from rubbing, i.e. 265/75 R16 as an example, 285s will more than likely rub with out modifying the hieght of the truck or cutting the bumper. Hope this helps.