the bleach didn't have an effect on the stencil at all, other than to erase the purple marker that i had used to trace. also, it's glued onto pretty heavy art paper.
to keep the bleach from spreading, i put little rolled tape strips under all the parts that wouldn't lay flat. also, the spray bottle created a pretty fine mist... you don't have to use a lot. just get it to where it looks like kind of a dew? on top of the fabric. you definitely don't need to get it soaking wet. haha sorry if that's totally confusing.