What should be included in the technical requirement communication checklist for custom pressure transmitters? Which parameters, if not clarified in advance, are likely to cause rework?

How long does the customization process for a custom pressure transmitter usually take, from submitting requirements to receiving a sample?

When signing a custom pressure transmitter contract, if the technical agreement does not clearly specify ownership of the right to change the diaphragm material, what disputes are likely to arise later?