Bill if u have a cool season grass issue, u can use oust to nuke that. I sprayed in fall and it didn't hurt the native grass. It's like having a clear slate for the switch come spring.
I wouldn't count weak spots out at this point. I've had some good chunks look real bad in year 3, and really start coming around year 4. It takes a little effort but this grass will grow. It's really a lot of fun.
Wow Looks great Bill!
Will that switch grass maintain itself after established???
Do not know where exactly you are, but in central Mn. hunters will not go into thick blackberry brush, so guess where the deer will go if pressured?