In all honesty I would not consider keeping a fish from Milll lake no matter what size.
This is just me, but the bigger the fish, the easier it is to let it go...from any lake! I do not fish to keep fish, and if I was going to, I wouldn't out of Mill. To each their own, but this is just me. Generally speaking in interior lakes I won't keep anything bigger then 17 inches or so. I know LOTS of people keep ANYTHING they catch...but everyone's different. I hope there;s alot of people who are also like me and I like to think if I let a fish go, someone else will have the chance to have the same enjoyment out of it that I did. plus c'mon, how good do those brooders actually taste? Not good enough to justify keeping them imho. Catch and release fishing is something that should be promoted, for everyone's (including the fishes) benefit. plus it just feels good to let 'em swim away to live another day, come back and catch'em again!!!