I too am a pre washer as I am allergic to the chemicals in the fabric making process. I will iron my yardage after I wash it. I used to be a a die hard Best Press kind of gal then I stumbled across the Bounce Pressing Spray. I love it! When I am ready to use a piece of fabric for a project, I will again iron and will do a light spray of either Best Press or Bounce Pressing Spray if it needs it. Might be a wasted step and a waste of product but I don't mind! When piecing, I press after every seam. I don't necessarily use anymore pressing product though. When my block is completed, I will give it a good pressing with a light spray of pressing product before I square it up.
(PS: I'm one of those weirdos that enjoys the ironing of my yardage after washing it. It is really cathartic for me, especially if I am in love with the fabric! Plus it gives me another opportunity to examine my fabric for any defects such as runs, snags, stains (even on brand new yardage!) or holes. I guess I spend a lot of time loving on my fabrics! I wonder if I should seek some kind of professional help. . . hmmm)