Giant Miscanthus is really expensive and takes a long time to establish. Plus it also doesn't always hold up to heavier snows. RC Big Rock will probably work well, but you could also try the Northwoods HD screen (which should hold up better to heavy snow) even though it's an annual and because sometimes the switch doesn't get tall enough for the grass to hide you well. It's often the seed heads that have to hide your head and shoulders and a 10' wide strip is unlikely to do that. You will probably need at least 20' no matter which one you use. And even that is on the thin side. HOWEVER, I don't live in Iowa so I'm not familiar with how well switch grows in that incredibly productive soil you guys have. Maybe it's normal for the regular Cave in Rock blades of grass to get 6'+ high.