How many are you looking at rearing?
Mine would sit on eggs year round if I let them, I had a Muscovy rear three broods last year
The most efficient way is to hatch all your eggs in an incubator.
If the duck sits on eggs she'll stop laying until the ducklings are weaned before she even thinks about laying eggs again., so you'd lose a good few months egg production by having mum hatch her own.
All depends what scale you're doing it on, if you want couple of dozen ducklings then two ducks will hatch them out fine, if you're looking for a couple of hundred then a few ducks would lay enough eggs for you to hatch that amount in an incubator.
It is lovely watching them grow up with their mum though
I like watching the transformation from the little ducklings constantly running after mum to the point when mum starts to run after them.
Then one day you see one of the boys move away from the rest of them and see the realisation dawning on him that he doesn't actually have to stay beside the rest of them all the time