FDA Traceability Requirements

Hi: I am currently on Vantage 6.10.536. Since we manufacture products that are used in Medical devices we are subject to FDA requirements for traceability of component materials. Most is done easily enough through lot tracking and receipt inspection of raw materials. However one item that is not so easy is epoxy that is used in the assembly of the products. We now assign lot number outside of Vantage and hand write them on shop travelers when used. However many customers are requiring all electronic records. In order to assign an electronic record to any given job, the epoxy could be added as a material line and issued by lot number like all other components. The problem is that the amount used is miniscule, varies greatly part to part and is essentially un-measureable. So issuing accurately as a material line while maintaining current on hand levels would become an inventory nightmare overnight. As a workaround we are considering the assembler adding the epoxy lot no as a labor comment when signing the operation complete in data collection. The down side of that of course is dependence on a production assembler which can be viewed as unreliable with high possibility of error since the lot numbers entered as a comment would not be verified as material issues are. Has anyone devised a better method for compliance with FDA traceability for items such as this?