I'm using the background image from the camera settings, and the back/front + alpha settings make it reasonably easy to see how I match the reference image. But it'd be much nicer if I could toggle while sculpting (here I need to select the camera first to play with the visibility). Is there a blender 2.8 equivalent to the neat trick with the layers?
I tried using Ctrl vs Alt. Now I have the expected result.
You have identified the problem. My Linux distro, Elementary OS, has some predefined hotkeys. I found them by holding down Super and Windows keys for 2-3 seconds and releasing them. I was given all the predefined hotkeys. I found on my distro that Alt+2 switches to workspace 2.