The settings you are referring to are no longer part of AMD Radeon Settings. You will need to rely on Windows or the Monitor controls. You may also consider reverting to the Crimson 16.11.1 driver.
You can use the "fix" posted here > Can't open Radeon Additional Settings...Part 3 A FIX !! / Guru3D.com Forums - View Single Post - AMD Crimsom ReLive 17.1.1 Download & Discussion
I am using the 16.11.5 control panel and the 17.4.2 drivers.