I've always 'auditioned' new blocks before I decide if I'm going to do a pattern or not. It's a habit that I'm glad I got into because there have been several that I just did not expect to work out and then somehow, the light bulb over my head goes off, I try it again and it's a success.
Taking scraps to find out if you're even going to like the block process or not is something I really believe in. For me, quilting has always been relaxing, fun and meditative, it should never honestly be 'work'. Just in the past year, I've conquered my fear of 'Y' seams and my fear of curves because I worked out whatever issues I had before I made the quilt, just by practicing on scraps. Now my quilting world has opened up to other possibilities and when the time comes to explore those, I'll be a lot more relaxed and comfortable. So I guess I'm excited to try, what's the absolute worse that could happen if I'm working on scraps first?