My client's media queries are based on the standard bootstrap media query sizes (576, 768, 992, 1200) and none of the existing emulators hit these marks exactly. So I created new ones based on /libs/wcm/mobile/components/emulators/ios/iphonex. I copied it and modified its cq:emulatorConfig properties, setting the device-pixel-ratio to 1 and the width and height to the approprtiate values.
After this I updated the emulator list in /etc/mobile/groups/responsive/jcr:content and it works.
The problem is that I've modified things under libs to get this to work. I've tried moving my custom emulators under a /conf directory, and pointing /etc/mobile/groups/responsive/jcr:content at this. This breaks the layout editor - the page refuses to load until I remove the custom emulators from the list.
Has anyone successfully done this without modifying /libs?