have a look at longreach aviation services, the website has a pretty fair coverage of contracts in China (but not all I expect) with quite detailed info, would give you a pretty good overview.
some other agencies are as generous with such info, many/most are not.
oh - and only you can answer your own question regards "best" contract balancing whatever's most important to yourself - time off Vs $$ Vs locations Vs....etc etc.
cheers