3/4 ton

Hello all, I am hoping to get some information re steel rims for my truck. I am struggling to find black steel rims in 17x8 8 lug. Everything I find is either 15 or 16" rims. Alloys seem to leak a lot in the cold temps. So, does someone make them and can they carry the same payload as alloys...

From all the reading I've done it seems like the 2500s sit higher stock than the 1/2 tons. Right now I have a 3/4 ton with a leveling kit and 3" body lift and I am taller than a 1/2 ton with an 8" lift. So my question is, what would be the max size tire I could put on without compromising the...