My top roost is about 4' high from the bedding floor made from a 1x3 with the 3" side flat. I did this so they keep their feet warm when the winter comes. It is plenty strong for the 8 hens.
I used two cedar branches, about 2-3 inches wide, in the corner of the coop about 16" high each to help them get up to the top. The hens who turn in early get the best spot on the top roost as the cedar branches are only on one side of the high roost. So once birds are up there the path gets congested. Sometimes one or two birds stay down lower.
They all like being up high and there is a hardware clothed window there for them to either look out, catch a breeze, whatever. My only concern is them getting down. Most of the time I see them just wait for a clear opportunity and drop down, trying not to crash into anything. Some seem reluctant to come down, either because of the height or because they don't want to lose their favorite spot. I originally had a ladder going to a lower roost but this gave them less room to plop down.
Some try to fly up to the top roost, but since the coop is only 4' wide it is tricky. I might put a larger ceder branch as the top roost (about 4" in diameter). I just figure it might be more ergonomically designed for their feet and easier to maneuver.
I don't use a poop board mainly because the width of the coop and this would restrict their movement (somewhat). Plus I figured the deep-litter method would work just fine. I just stir up the bedding in the morning and toss in some scratch so they turn over the bedding themselves. I will see how this method works for a while.
I have 8 hens in a 4x8 coop, so that should be about right.