Hi,
Have you tried using the water tool to determine how much of your water and how much distilled water you need? The new water tool lets you include two waters and mix them, so if you start with a base water and add an amount of distilled water you should be able to balance the profile.
Then its just a matter of adding both waters to the recipe (your regular water, plus the correct amount of distilled water plus any water additions if needed) to get to the overall solution.
Cheers!
Brad