if it is puckered you didn't add enough shirlene oops sorry graciegirl
I also add stabilizer for FSL designs, if I see any tearing at the stitch edge. Density is the one clue that you may need additional stabilizer. Live Laugh Download Stitch!
If your design is puckering, you might consider another layer. There is a rule of thumb on the number of stitches per layer of stabilizer, but right off the top of my head, I can't think of it. Sorry. Good question.