Not sure I'd want that much vinegar taste to them.

I suppose in theory it might allow you to get by with a weaker, more diluted vinegar to water ratio if you wanted to for some reason but the ratios needed would be an unknown.

5% is plenty safe as long as it isn't diluted more than 1:1 and the taste is a known quantity so i can't really see any advantage to the stronger stuff. JMO

Dave

What you would do is use 56% of the vinegar called for (assuming the recipe was written for 5%), then make up the rest of the total volume of liquid with water.

So for example the recipe called for 2C of 5% vinegar and 2C of water. You would use 2x.56= 1.12C or 9oz of vinegar and 4-1.12C= 2.88C or 23oz of water.

If you were using say 4% rice vinegar, you'd use more, 1.25*2C= 2.5C vinegar and 1.5C water in that recipe.

But why use 9% vinegar in a recipe calling for 5% when 5% is so widely available?

Here is a link that might be useful: A Gardener's Table discussion of rice vinegar