Your goal is about twice our present flock's production of 10 dozen a week, so let's see what the numbers say.
You'll need 45 hens that lay 6+ eggs a week, every week. 320+ eggs per year, per hen. Only the Red Sex Links, with ISA Browns leading the pack, will do that, on the brown egg side. The ISA has a great personality, which is nice. You won't find them nearly as flighty as a Leghorn. 20 dozen eggs per week, means 40-45 of the girls will have to lay every day. That is a reachable goal with the Sex Links. Be sure to factor the occasional broken egg, and their "days" off for whatever reason, yes, they do take one now and then.
45 hens will also consume 70# of layer pellets, @ $14/50# every week, and sometimes more than that. They'll also drink 15-16 gallons of water per week.
Even so, in winter, to keep that level of laying going, you'll need to have a small light come on at 4 am and burn until 4:30 pm. You need them to go to roost under natural light, so the light snapping off doesn't catch them unaware.
I'd also say this. You'll have to have your next 40-50 pullets ready to take their place in a year. To maintain a super high productivity rate out of 40-45 hens, you won't be able to keep them more than a year, or at the most two years. Top quality feed is also a plus. Best of wishes on your new project.