A method of molding a multiple layer container, comprising: (a) injecting a first flowable material into a mold cavity (220, 375) configured to form a molded container, the molded container having a closed end and an open end opposed to the closed end and comprising the first flowable material, the mold cavity having a nominal design thickness and comprising a non-axially symmetric portion proximate to an injection location of the first flowable material, the injection location being at a center of the non-axially symmetric portion, such that distances between the injection location and points about a periphery of the non-axially symmetric portion vary around the periphery of the non-axially symmetric portion of the mold cavity, such that the closed end of the molded container also comprises a non-axially symmetric portion, and such that the injection location is at a center of the closed end of the molded container; (b) co-injecting a second flowable material into the mold cavity and interior to the first flowable material; and (c) modifying flow of the first flowable material and the second flowable material with a plurality of adjacent flow leaders (430a, 430b, 535, 535a, 380a, 380b) defining a plurality of different respective thicknesses in the non-axially symmetric portion of the mold cavity to produce a symmetrical flow boundary downstream of the plurality of adjacent flow leaders and to cause the second flowable material to flow throughout substantially the entire mold cavity, wherein the plurality of different respective thicknesses are different than the nominal design thickness of the mold cavity. (a) injecting a first flowable material into a mold cavity (220, 375) configured to form a molded container, the molded container having a closed end and an open end opposed to the closed end and comprising the first flowable material, the mold cavity having a nominal design thickness and comprising a non-axially symmetric portion proximate to an injection location of the first flowable material, the injection location being at a center of the non-axially symmetric portion, such that distances between the injection location and points about a periphery of the non-axially symmetric portion vary around the periphery of the non-axially symmetric portion of the mold cavity, such that the closed end of the molded container also comprises a non-axially symmetric portion, and such that the injection location is at a center of the closed end of the molded container; (b) co-injecting a second flowable material into the mold cavity and interior to the first flowable material; and (c) modifying flow of the first flowable material and the second flowable material with a plurality of adjacent flow leaders (430a, 430b, 535, 535a, 380a, 380b) defining a plurality of different respective thicknesses in the non-axially symmetric portion of the mold cavity to produce a symmetrical flow boundary downstream of the plurality of adjacent flow leaders and to cause the second flowable material to flow throughout substantially the entire mold cavity, wherein the plurality of different respective thicknesses are different than the nominal design thickness of the mold cavity.