Golf balls and systems for applying one or more polymer layers to a golf ball construct are disclosed. As but one example of disclosed systems, a method of forming a golf ball construct includes positioning a core or mantle portion of a golf ball in a cavity, opening a valve gate adjacent the cavity to cause viscous polymer to flow through the valve gate, into a short runner and into one or more radial runners that at least partially surround a circumference of the cavity. The polymer layer is allowed to solidify to form a solidified polymer layer, and the golf ball construct is removed from the mold cavity.