Salary adjustment for China?

I don't think there exists a "normal" incentive bonus amount. Both your salary and any additional stock options, shares, incentives will be at the mercy of company policy. Small companies may be able to offer one thing, while medium to large companies may typically offer another. Plus, your skills, work experience and ability to speak Mandarin also come into play.

Furthermore, more and more companies are not offering the glamorous and comprehensive expat packages of old - meaning that housing and assistance with school fees are no longer pretty added extras that you can 100 percent expect. Still, even if you get more of a local package, you can try and negotiate for some benefits (try for housing and any tax incentives you can). 

I would recommend having a look at the Salary Information page gathered by the Hudson Group (human resources consultancy that addresses Asia). 

Also, where in China are you being asked to move? Keep in mind that the cost of living in Shanghai or Beijing will be world's more expensive than that of life in Bangalore or Chennai.