I live close to the Missouri River in Montana and trout Spey is booming here. The headhunters fly shop has been a big influencer on the topic. They even work with Whitney Gould and Mike McCune, 2 big names in the Spey world. The river is really wide and with a flat flow, perfect for swinging. I pretty much only swing for trout and will switch to my single gander only for dries.