One ounce is usually about one drink, give or take. Technically, most organizations use 1.5 ounces of 80 proof spirits, 5 ounces of table wine, or 12 ounces of beer to represent one drink. If you go to a bar and are getting one ounce every two drinks, I’d suggest a change of venue.
There are a number of factors that modify the rate at which you metabolize alcohol. You excrete about 5% unmetabolized via the lungs (which permits the police to use a breathalyzer on you), and some is excreted unmetabolized in the urine. The one drink an hour statement is very variable from person to person - some people have a greater number of alcohol dehydrogenase (ADH) enzymes in the liver to metabolize the alcohol with, so they can clear it quicker. There is also a genetic component to the number of enzymes in the liver, but it’s not totally genetically determined. Liver damage caused by prolonged or heavy drinking can result in lower counts of ADH, and alcohol will accordingly take a longer time to be eliminated. Naturally, if you’re drinking on an empty stomach you’ll absorb the alcohol a bit quicker than if you had a full meal beforehand - the quicker absorption will result in faster intoxication and a marginally faster elimination, but the real determining factor is the enzyme count in the liver. Once you saturate those enzymes, you’ve reached your peak metabolic rate - the alcohol molecules attach, get modified, and leave (to get replaced by another alcohol molecule until you have no more unmodified alcohol). The fact that you can’t really eliminate it any faster once you reach peak rate is the reason that you can get SO intoxicated - you drink faster than you eliminate, and the unmetabolized alcohol starts playing with your organs. Most people eliminate between 7-10g of alcohol an hour, regardless of body mass, but bigger people may feel less intoxicated in some situations because they have more total body water to distribute the alcohol over. Men also tend to have more total body water than women, and as a result women consistently show a higher BAC when presented with equal alcohol doses/kg.
Chronic drinking can upregulate the ADH enzyme in the liver, resulting in increased metabolism. Paradoxically, it’s also associated with destruction of liver cells and cirrosis, resulting in slower metabolism - just depends on what stage you’re in.
Clear as mud, right?