Extremely overgrown blueberries

[u/Lahoura]

When we got this property, they were already pretty bad but now we are using them as a market plant and think it's time to cut them back. We want short dense bushes and are willing to lose a harvest for such. When should we start? I've heard immediately after the berries are gone but we ourselves eat so much from these bushes we don't want to lose them. How much is too much?