Yeah, 10-20 seconds seems reasonable for your normal 9-12" fish. I get brookies to me in well under 5 seconds probably, though it might take me another 5 seconds with it in the water at my feet before I get my hands free and such for the release, or picture.
Big fish will make it take longer. The difference in the "fight" isn't that great, where the difference comes is in the landing. Normal fish you can pull that head up and just drag em right in. When they get big enough where you can't get the head up and can't stop the panic runs when they get close, then that can take a little time. Still, even on steelhead, I think 1-2 minutes is typical.