Couple things I have learned
1. Mom taught me to let the starch set a little before ironing, like letting it dry a bit, 30sec or so. This sets the starch better and also prevents the 'dusting' you get when you iron wet starch (kinda like starch dandruff)
2. Just starch the front, doing both sides is kinda a waste of time,
3. Starch should not make it "paper" stiff. It should feel like the fabric was unwashed....so kinda like when it still had the sizing in it. or slightly softer.
4. Trying to make it feel like paper causes it to have dandruff.
apparently there is a max amt of starch a fabric will take.
I use best press because I like how it doesnt flake as bad when my impatience gets in the way of the starch drying.
If you have long bias cuts (like more than 6-8inches or so) do a long basting stitch along the bias close to the edge. It will keep the fabric from stretching and will be hidden in the seam allowance anyhow. Starch alone will not keep long edges of bias from stretching. I generally work with bias less than 8inches, so I dont baste.