The type of ribbon you use has alot to do with whether you need to stiffen a bow or not. Good quality grosgrain really doesn't need any additional stiffening. It's also much easier to work with, esp when first learning.
I think you will find that satin and organza are much harder to handle when first learning.
Warning about using the microwave.....you need to place JUST the ribbon in, NO CLIP or other metal or sparks will fly!