Why would running it at 6ohms put more stress on it? I figured running it at 4ohms would put more stress on it. Hey that’s why I asked the question in the first place? I didn’t know what setting was ideal in this situation. 
The 6 ohm setting on receivers is a legalistic fudge. It deliberately throttles the output and is the worst thing for 8 ohm or 4 ohm.
Most decently designed receivers will have no problem driving the Maggie 4 ohm load. The question is whether they can drive them loud enough.
I used to have Apogees and Maggies and drove them to comfortable levels with Anthem and Onkyo receivers.
However, they need to be decently designed. Recently I briefly owned a Yamaha receiver that shut down at even lowish levels when faced with a less than 8 ohm load.