The present disclosure relates to a container assembly for use in a planetary mixer, which may comprise a jar with an inner wall, an adapter in contact with the inner wall of the jar, a metered-dosage dispenser having a tubular body, and a lid attachable to an rim of the jar, wherein the adapter, if included, may be configured to clamp to the metered-dosage dispenser, if included, and the adapter, if included, may be further configured to keep the metered-dosage dispenser away from the inner wall of the jar, wherein at least a portion of the metered-dosage dispenser, if included, may be configured to allow visibility of at least some contents inside the body of the metered-dosage dispenser from outside the body of the metered-dosage dispenser, and wherein the body of the metered-dosage dispenser, if included, may have a height-to-base ratio (HBR) between 0.75 and 1.5 at half volume.