I had my first experiences with blocking fabric the other day. Again, my partner's mum who's been doing this since way before I was alive. We used the ironing with steam (on acrylic, which would freak me out so much) and it is just so amazing how well she did it. We couldn't stretch it enough to pin it to the right dimensions without the pins flying off and she managed to iron it out to an inch longer. Not the best thing, but that is just amazing.