Yeah, worst case nothing to lose. Can sit on X until 11.2 beta comes out and restore from that backup (which I thankfully did with iTunes before trying to revert to 11.1. It worked...except for apple health.)
I am going to try the .plist method tonight off that backup with the X. If the health data fails, I'll just set it up new with basic apps until the 10.2 beta comes out.
My Activity Ring & Health data is most important thing on my iPhone So I'm certainly NOT going to try the downgrade from ios 11.2 to 11.1 on my iPhone