That should be plenty of steady work. It's also depending on how many project managers and engineers Xi'an has on their pay roll to be able to take on anymore different kinds of projects.
Xi'an will have to do quite some extra hiring once the Y-20 goes into production in 5 to 7 years time. But for now i think most of whatever developers and engineers they have on their payroll will be working on the Y-20 project.
I correct myself Xi'an is involved with the ARJ-21 project they build the wings and fuselage. Once that plane gets certified there will be plenty of work there.