That's exciting, you're going to have a very nice flock!
If I were you, I'd pay special attention to reply #5 from JThornton. He's very good at building things and provides good detail on how to do it in his posts. I have 12 hens and one rooster and like JThornton, I use a single community roll out nest box and I can't recommend it more highly. Mine is from HenGear.com and is the medium nesting box, which is 24 inches wide and 11.5 inches deep in the nesting area. It's good for up to 20 chickens, they have smaller and bigger. I have Golden Comets and Leg Horns, your's are probably going to be a little bigger, but I think it would still work. To be safe build one like JThornton, that's plenty big for your whole flock.
I just started with chickens last August, and knew nothing. Thanks to this forum I've been successful with my flock. I'm surprised people still use individual nesting boxing, when the community roll out nesting boxes work fine and have a ton of advantages over individual boxes. First just one box much less space and material. Second roll out boxes usually use a astro turf mat that lets dirt fall through, set on top of half inch hardware cloth that also lets dirt and debris fall through, no poopy straw to replace. Third the eggs roll out, can be to the back or to the front, and are very, very clean, no more poopy eggs. Fourth since the eggs roll out right away and are out of reach of the hen, they can't ever start egg eating.
I really like how clean the eggs are, we keep them in a roll down skelter by the stove, and since they're clean when we get them, we don't have to wash them, which removes the protective bloom. With the bloom intact an egg is fine at room temperature on the counter for over a month. Now you're cooking with room temperature eggs, which any chef will tell you is more desirable.
After all that, I simply can't imagine why anyone wouldn't use a single community roll out nest box.
Here you see the perch bar, nesting astro turf mat, and the slope of the nest (mine is adjustable).
Here you see the full box, 24 inches wide x 11.5 inches deep. If you look closely you'll see there're two hens in the box.
Here's the lid open on the back side of my nesting box. Mine goes through the wall of my chicken tractor, although mine is also able to be under the perch, out of the box from HenGear, you choose which configuration you like better.
You could build your own like Jthornton, or buy one in perhaps a larger size than mine, but you could always call HenGear and ask them. They have a huge chicken farm and sell these boxes as well.
By the way, go on
Amazon and get one of these (holds about 22 eggs), or even two like I did, and add the sections of the second unit on top of the first one. Search for plastic egg skelter, should be about $10.
I love our skelter, it's the only the only system I've tried that my children don't mess up. It's so easy, new eggs in the top, use eggs from the bottom. No more "which eggs are these" problems.