You need to do some more searching. But USUALLY, the smaller the number, the smaller the blade.
www.fineleatherworking.com/leather-sewing-awl-blades/
www.etsy.com/market/awl_blades
www.mainelineleather.com/products/awl-blades
redoxbrand.sagecreeksaddles.com/product-category/handstitching/awl-blades/