Starter Conversions

[splatgirl]

Hello. About to fully reveal my right-brained blond side here:

I know, this is kind of ridiculous because it's just basic math but it seems like every time I go to use Leader's (fantastic) "Bread Alone" book, I stand there with it open and freak out and waffle because I can't figure out the final formula (as in ready to go into the final dough) for his starters based on mine. And I know it just shouldn't be that much work. It doesn't help that every recipe has you refreshing the levain as the first step which in my case seems unnecessary since I've already done that in prep for a bread bake anyway.

I guess basically what I want to know is: from the perspective of an already active, freshly refreshed 100% hydration white flour starter, is it adequate to assume his liquid levain is 130% hydration and ~100% white flour, and that is his stiff dough levain is 55% hydration and 9% whole wheat, 91% white?
Can someone translate that into:
x grams of my starter + y grams of water + z grams of whole wheat (for the stiff dough)=Leaders starter

tia
s.g.