Ive made mod using your idea, code and symbol graphics aswell.
Idea of other pump for doing this was not good im my opinion couse i think assembly machines for such operations are enough.
So my mod is using assembly machines to fill/empty barrels like it was working with crude oil by default.
Its allowed by default "Fluid Handling" research and not using water couse in my opinion its pointless operate with water like that.
So as u are main creator and im using your idea and graphics ive not publish this outside and using just by myself and one other player.
If you want i can send this mod and you add it for yours so potential users will have choise to use this nice feature in two other ways.
Thanks and hope factorio stuff soon make it default feature.