This crochet size and weight infographic details all the different yarn weights and the specifics of each. It breaks down the yarn type, weight, wraps per inch and ply. This infographic also includes a chart of different crochet hook sizes.
I suggest finding an old worn out chair, even a rocking chair at a yard sale or thrift store, spot spray it white and spot sand it to create an olden look. Then put a planter with a fake poinsettia in it and place on the seat, if you desire.