We recommend getting the largest size you are comfortable with so that your vest will 1) Fit your child as they grow throughout the program and 2) Fit over your jackets/sweaters during the Fall/Winter/Spring season. Most people should buy Child Large and Adult Large vests.
There are several suppliers online for leather vest kits, such as
Standing Bear’s Trading Post (Ask for the 10% discount):
There are also Embroidered Cloth Vests:
See also Tips for adhering patches to your vest using an Iron and Hot Glue Gun.