I installed probably the same Napa steering box in place of the advance auto box I had the past two years. I went from about 6" of play to the same 1/2" play you had. I'm satisfied with it, even though there's a tiny bit of play. I don't feel like swapping it out again lol.
Don't buy Advance Auto boxes. They suck. The first one I got had a bad clunk in it so it came out two weeks later and then the recent box lasted about 2 years, 6k miles, and had 6" of play in it. Terrible boxes.....