How long does alcohol stay in your system? does how much you consume mean it's in your system longer? vice versa ?

Depends on test: If only blood alcohol levels are checked, those are usually normal at about 12 hours after last drink, sooner if amount imbibed is small. Urine test for etg may be positive for 5 day after drinking. In a chronic drinker CDT test may be positive for 2 weeks. See this site for rate of alcohol clearance from blood: http://www.ncbi.nlm.nih.gov/pubmed/1940231