It's not super-convenient (it takes two swipes to get to), but the Android Wear Mini Launcher ( https://play.google.com/store/apps/details?id=com.npi.wearminila

It's not super-convenient (it takes two swipes to get to), but the Android Wear Mini Launcher ( https://play.google.com/store/apps/details?id=com.npi.wearminilauncher&hl=en https://play.google.com/store/apps/details?id=com.npi.wearmi... ) has a settings screen which includes a number of useful options about the phone's settings, including volume.