I agree about the roosts - they are too low in relation to the nest boxes. As appealing as the design is in other ways, the low roosts would be a deal breaker for me. You will constantly be dealing with poop on your eggs, you simply can't teach a hen not to sleep (and poop) in a nest box.
Also, you don't need 6 nest boxes for six hens. Three is more than you need.
My sister and I bought a similar design for our six hens, but the roosts are level with the top of the nest boxes, since they're naturally inclined to roost as high as they can get, we have no trouble with them sleeping (and pooping) in the nest box. If we get dirty eggs, it's because the bedding needs refreshing - you also simply can't teach a hen to wipe her feet before she enters the nest box.
Our coop has three nest boxes, but they all like to use the same one.
The run size is OK - they're happy staying where the food and water are anyway. But with a run this size, you should also give them access to the great out-of-doors for at least a couple hours every day. The safest way is a tractor.
My sister and I decided to buy a coop simply because we don't have the construction skills and didn't want to learn on the job. The coop we bought is very well-made, I doubt we could have done as well. We bought it from a local guy who makes them, and if we had wanted a change, he would have done it. If you don't have the skills yourself, you should look for a similar person, we found our guy through Craig's List.
Edited by jacqueg - 4/2/16 at 4:12pm