Is there a type of ring you would recommend?Yes, Sasquatch you can adjust the straps on the rings out on the market to even them out as they hang.
I hang mine on a power tower or the field goal at the local football field at the HS that is close to my house, or any other that I'm passing while around town. Soccer field goals work well, too.
Swingsets are another option or monkey bars( these are typically not high enough ).
You can of course, set them into your ceiling or garage or into a heavy support beam in the ceiling roof.