I'm making a 100% alcohol mixture where the recipe needs to be followed perfectly or else you get a low quality brew with 0% alcohol.
For reference, this is the brew.

purealcohol:
name: Distilled Water/&cRubbing Alcohol
ingredients:
- BEACON/7
- NETHER_STAR/2
- DIAMOND_BLOCK/64
cookingtime: 0
distillruns: 0
wood: 3
age: 3
color: 'FBF8F7'
difficulty: 10
alcohol: 100
lore:
- ++ Accidentally messed this one up while trying to make vodka.
- +++ This probably isn't safe for consumption.

I want to make the alcohol level 0 for Distilled Water, and 100 for Rubbing Alcohol. Is that possible?

If you wouldn't follow the recipe perfectly you would get a ruined potion, wich has just a small amount of alcohol, is that what you are trying to do?

yes, exactly that! sorry if i didn't explain it too well

You could try difficulty: 9, then you would get Distilled Water when you mess up the recipe, with very little alcohol.

Also you always need either 1 or 3 names for the potion, so in your case:
Distilled Water/Distilled Water/&cRubbing Alcohol

I see. Around how much alcohol would the distilled water have?

The "second tier" of distilled water so to speak

I don't think anyone could even make the second tier with that high difficulty, it would either be perfect or ruined. But you would have to try i'm not sure really