I just recently got a Skip 1s to replace a dying Harmony 950. The hardware and app appear capable, but the App feels a bit rough / easy to confuse. I was also pretty quickly looking for adding secondary functions, not sure why the app can only do it for the cursor buttons, because it turns out, the remote can do it as it is.
If I export the remote configuration, I can just manually insert additonal mappings in the "colorModeMapping" List of the desired activity. After reimporting the config file and syncing to the remote, the commands seem to work and even show up as assigned in the color mode mapping settings of the respective activity, but obviously this is way less convenient than just adding these "shift" mappings in the GUI... Really don't understand why that limitation is there.