Lower is NOT better from any data that I have seen and it makes no sense. It may be a ploy to charge more for less by some marketing person. But, if you find some data we will gladly read it.
The larger cans with larger sprays are better. It is good to know that the spray deteriorates in power over time for some reason and the cans should be replaced once a year. If you can find one where it empties the entire canister in one squirt, that would be good. Once you have squirted even a little, it is my strong opinion that you should replace the canister. And, she needs to practice as was mentioned before. So when you find the one that looks good, get three or four so she can practice with a couple of them at least.
There is another false claim as well -- that people need less pepper than bears or dogs. That is not true. Bears and dogs have far more mucous membranes, eyes, open mouths, wet noses, to hit with the spray AND they are not as likely to be hopped up on drugs or to be used to being sprayed, like people are. Use a far stronger concentration for people than for animals.. And, remember... many bad guys have been sprayed now and it's not as useful as it was many years ago when it was first used. 10-15 years ago pepper spray was new and unique, it was mixed with alcohol or other thinners that helped it be more effective and the BGs were surprised by it. Now some of them joke about spraying the pepper spray in thier chili beans to give it some more spice.
