I heavily starch my fabric by spraying on Sta-Flo. I am now using about 8/10 starch. I have had no trouble with sewing bias edges. Last year, I made a red work quilt. Because, no matter how careful I was, I'd get some red threads that showed through. My solution was to use a very, very, sheer iron-on interfacing behind each block before I started the embroidery. That kept threads from showing and I doubt that anyone could tell that the blocks were interfaced once the quilt was finished. The quilt was not at all stiff. Best wishes with whatever you decide to do. I'm just a huge fan of heavy starch.