I was 5 in 1980. I grew up in Idaho. I was raised by basically non-drinking parents. I had no idea that in 1971 there were many disparate ounce measures in different bottles of booze. This issue has never been on my radar before. As a bartender, and now a manager, the simple (and sometimes not so simple) math of the cocktail and bottle to person ratios have occupied my brain at length. It must have been terribly frustrating for the party planner or bar owner making standard drinks and always running short on one thing or another. This sounds very much like the marketing plan schemed up by the hot dog and the bun people. No matter what there is always too much of one thing and not enough of the other. Thankfully, bottle sizes were standardized in 1980 and so I don't have to worry about it now.
That being said... Have you ever felt slightly pissed off because you feel like your wine pour looks particularly short in a restaurant? The 90's and 20000's have totally distorted our sense of what a regular portion of a food or drink item should look like. I was in a gift shop recently and there was a wine glass predominately displayed as being able to hold an entire bottle of wine. While this struck me as a product of our super-sized nation it wasn't that much larger than many wine glasses I have seen in restaurants. When working for The Capital Grille, where they have large beautiful glasses, the perception of "short pours" was eliminated by bringing over an individual carafe of wine every time wine by the glass was ordered.
So the question is what is the proper portion size? In 1971 the portion for a glass of wine was 4 oz. If you read any diet book this portion size is also used. In restaurants 6 oz. is standard. For a highball- the "and" drinks like gin and tonic the pour should be 1 1/2 oz. of liquor. A rocks drink, cordial, port and straight up drinks should have a liquor pour of 2 oz. Many martini glasses can hold 6 oz. of liquor or more. Bartenders also have a knack for filling up glasses regardless of size and standard portions. All this being said I believe in measuring product when mixing your own drinks and following recipes. Making cocktails is like cooking. It isn't as scientifically important to get portions as precisely correct as in baking but not measuring can really mess up your drink. If you are just starting your exploration of mixology, then for the love of all that is holy, buy a jigger- the little measuring tool- and follow directions. Happy drinking!