How much I can save in HK on a salary of HKD 40000?

Hi All, I am in talks with a prospective employer in HK and most probably I will get an offer around HKD 40,000 Per month. Though it is not clear at this point of time what other benefits my employer will provide me(like health care benefits etc). I am thinking of negotiating further to see if I can push it to 50K or 55K Per month. Do you see any scope for further negotiating on salary/benefits with my prospective employer beyond 40K per month. I am IT professional with over 8 years of experience and most probably would be working on financial services/investment banking related software development. I have to relocate from India with my wife and 6 month old kid. So I did some research on HK's cost of living and estimated my monthly expenses at around 26000 (including house rent and excluding insurance costs (healthcare and others)). I provisioned around 16000 as rent as I was looking for a 650-800 SqFt furnished flat. Does my estimates look reasonable? or am I over-estimating/under-estimating? Any information here is highly appreciated. Regards Srikanth