What wheels can I use these hubcaps on?

[wldcat10]

I'm a little confused and have read that these hub caps don't always fit without a lil' bit of modding? I'm looking to find what wheels I can buy to put either one of these hubcaps on without me having to mod them? Would the factory steel wheels work? My truck is a 6 lug if that makes a difference in anything? Below are pics of the hubcaps I'm looking to buy, just want to see if it's going to be more difficult to find a wheel to fit right.