Flow meter validations

I have 3 “in-line” flow meters and 21 points-of-use for highly purified water. The flow meters will be used for batching water into manufacturing vessels during the manufacturing process.
The hose is food grade quality, 6 m long and attached to the flow-meter with a tri-clamp.

I am validating each flow meter across a range of volumes.

Do I validate each flow meter over a period of three days at the selected batching volumes?
Do I need to validate each flow meter at each point of use in the loop - or can I select points-of-use at beginning, middle and end of the loop?

Any comments would be greatly appreciated.

Thank you