in the O&G industry maybe the SPE 2008 salary survey could give you a help or a guidance in this matter. Do a search in google for the above mentioned document since it is public; and you can save a copy of it in your venues for reading and consultation.

As per grades and salaries you are right maybe that info is not on the internet but if RasGas has contacted you you should approach them and ask at least the grade.

In sites like monstergulf or even bayt some positions posted sometimes give information on salary package on a per annum basis. Just check and do the maths.

Yet another place to look after positions and salaries could be

http://www.oilcareers.com

Regards!!