Card-based systems – like Kanban and Constant Work-in-Process (ConWIP) – can be simple yet effective means of controlling production. Existing systems, however, can be criticized for their limited applicability and scope. First, card-based systems have not been successful in the production environments that are arguably most in need of their help: complex job shops that produce low-volume, high-variety products. Second, while most existing systems simplify shop floor control, other planning tasks – such as the estimation of short, feasible due dates during customer enquiry management – are not supported. To overcome these limitations, a card-based version of Workload Control – known as COBACABANA (COntrol of BAlance by CArd-BAsed Navigation) – was recently proposed that uses cards for both due date estimation and order release control. This unique combination makes COBACABANA a potentially important means of controlling production, particularly for small job shops with limited resources. However, the original approach had several shortcomings. This paper refines the due date estimation procedure of COBACABANA to make it more practical and consistent with the order release method applied. It then uses simulation to demonstrate – for the first time – the potential of COBACABANA as an integrated concept that combines customer enquiry management and order release control to improve job shop performance. Results also suggest that the need for processing time estimations can be simplified, further facilitating the implementation of COBACABANA in practice.