I don't know if standard drinks work that well, the need to be able to focus, read and do mathematical calculation. How about a instant visual indicator.
If a can of beer had a line right around the can showing how much pure alcohol was in the drink. Wine bottles could have a the slightly higher line.
Off
course , in manufacture this is highly possible as all volumes and amounts are controlled and known, Manufacturer's would be open to design the line how ever they see fit ,for branding incorporation.
Out in the wild, this would not work as drinking vessels are many and concoctions drunk are varied. A few standard drinking vessels with plimsoll lines could be etched up. A standard wine glass, beer glass, shot glass and spirit glass. Of course, with these glasses the average alcohol content would need to be calculated as each group has it's range of alcohol contents. Cocktails could be done with a set. A particular glass chosen dependent on the cocktail mixed.
Or, visually over time, if in a controlled environment, the bar person can fill a measuring vessel with your personal pure alcohol intake, in equivalent water.
Then again, it can also be done personally by having a empty glass at the start of the night and slowly fill it with water as alcohol consumption ensues.