Here is the simple chart that I converted sourdough ( levain) to raisin yeast water ( levain).
* Jeffery Hamelman doesn’t count the amount of the sourdough starter because the little amount of the starter will be a portion of dough that we loose during the process of making bread. I don’t calculate the amount of sourdough starter for my raisin yeast water levain because it is easy for me.
If you want to make sourer bread like Tartine’s bread, It is better to use 20% raisin yeast water as to 100% preferment flour. I made this kind of bread before.
Here is the example of sour bread with raisin yeast water that is based on sourdough levain bread.
If you click on the PDF↓, you can see it in a large size.