Pre ferment development

I have working my way through FWSY and have decided I like using pre ferments as opposed to the constant upkeep of a starter.

I want to adapt a recipe I love from Artisan Bread in 5 minutes a Day to using a polish. It is a mix of white, WW, and rye. In FWSY he has an adaptation of a 70-20-10 mix but only for the overnight straight dough.

so here is my question: should I mix my poolish with the same ratio of flour or make it with all white flour and add the whole grains to the final mix.

I will try both methods and see which I like better.

Dan