Hmm, seems those "reading is fundamental" classes were a good thing, as I saw several recipes in the article that someone with a functioning brain could use to make their own hand sanitizer.
I also didn't have to employ algebra. A simple fraction or percentage (often learned around the 4th or 5th grade) sufficed. You can get 70% and 90+% alcohol. You want at least 60. So don't add very much aloe vera to the 70 and you can add up to 1/3 of the mixture be aloe vera if using 90%+.
I have small spray bottles. I fill one most of the way with 70% rubbing alcohol, top it with some aloe vera but no more than ~10% of the total volume of the bottle, and add 10-12 drops of tea tree oil. Nice on the skin, as effective as a store bought sanitizer. You may also use a 150+ proof alcohol like bacardi 151 or everclear, but those will be around 75% alcohol. And no, what type of alcohol doesn't matter in the slightest. So the BS about using vodka is exactly that, BS, since 80 or 100 proof vodka straight up would be 40 and 50% alcohol, respectively.