Master is the branch for working towards next user release. So now Nexus is done Master should be for any Omega changes.
All PR's MUST be made to Master first, if a fix then once merged into Master a seperate PR to be done to the relevant release/s branches.
Once Master is in a fit enough state for an Omega release, only then create an Omega branch at the point a PR is ready to be made to skin repo for the update to users.
Once Omega branch is created then Master becomes working branch for v22.
Seems to fit with https://github.com/xbmc/skin.confluence/compare/master...Nexus so go for it.
In future I'd suggest: