How to manage two possible resources for the same operation

Hi,

Our customer manufactures chemical products. In some work centers, they may use two tanks with a different capacity.

The same product can be produced in one or the other tank, the decision is made by the prodcution supervisor.

How would you design this case?

• Assign the two different resources to each operation, keep one work definition, remove the un-used resource before releasing the work order.
• Assign the two different resources to each operation, create one work definition for each resource.
• Any other idea?

Many thanks.

Alex