I would wash the fabric with the colour catcher using the same settings that will be used to wash the quilt it will be part of.
I am a big fan of prewashing all my fabric, which then is wound onto comic book boards (I always buy 2 yards at a time, and I like to work from a big stash). I wash quilts in the warm water wash, cold rinse cycle, and dry with heat.
That means I have to pay attention during quilt construction because the quilts are going to get a good workout when laundered. I use a slightly smaller stitch length than "normal", and make sure everything is going to stay put.