substituting one starter type for another
I have a question about whether you can easily substiute a biga starter (a starter made by adding a very small amount of yeast to a flour and water mixture) with a liquid sourdough starter. The reason I am asking is that I have been used to making a lot of breads with Hammellman's formulas that use a sourdough starter. but recently I have started making some sandwich breads out of Amy's Bread (revised edition) that use a biga starter. I have no problem using the biga for these breads. They have come out really well- I especially like the oatmeal bread with pecans. I highly recommend it. It's just that I feed my sourdough regularly (because I don't want to risk losing it!!), and it would actually be easier for me to use that rather than create a biga for the sandwich breads. I understand how I can exchange a thick starter for a liquid style, so I could adjust the sourdough for a corresponding hydration, but I am wondering if the sourdough would work as well.
Has anyone done this routinely? I could just perform my own tests, but I am wondering if any of you has done this already. I would appreciate any input on this. Thank you!