Fab-ra-holic

I am planning on making a quilt with the Kite Plus Ruler. All cuts will be on the bias. The video says to starch the fabric really well to help with the stretching. My question to all of you is, has anyone ever used a very lite weight iron on interfacing instead of heavy starch. If so, does it tend to stiffen the quite once it is complete. I don't want the quilt to be too stiff. Hopefully my question makes sense.

Thanks in advance
Peggy