Finding the appropriate balance for Engineer-to-Order (ETO) prefabrication firms between work in process (WIP), finished goods inventory, buffer hedging, transportation time and the field installation consumption rate is difficult to determine. The difficulty arises due to the high degree of variability in the product offerings to meet the architectural and performance requirements of different projects and locations where the products will be delivered and installed. Variability also exists in plant production rates, on-site equipment availability, and efficiency of on-site installation crew. This paper examines these challenges of ETO panel fabricators and evaluates potential applicable solutions.  In addition to the analysis for a single firm, a survey of firms performing similar work spread across the continental US was conducted to gauge their respective solutions to similar problems. The majority of the respondents plan to commence fabrication in advance of field operations and half of the respondents have experienced situations where they had to slow or halt production of the panel products due to storage constraints.