If you wish to Range them without tanking, then your best bet will be in the Smoke Dungeon: I did a quick edit on the map, and I circled the area that two Dust Devils are at, which is a great spot to Range. And then just below that, I put two white dots, which represent the two safespots that are commonly used for that location. This is, in my opinion, the best safespots for Dust Devils, just because it's easy to use, and meleers won't want to attack those, since they're slightly more spread out, and only two of them. I probably ranged 75-85 on Dust Devils, with Blue Dragons in there as well. So, I spent quite a bit of time there. Things have changed since, so I don't necessarily know all the best methods though, with new equipment. It might just be easier to tank nowadays, etc.