Well, I have a ladder style roost (I'll get pics tomorrow) but am changing over to a 2x4 single level set-up because I don't like the ladder style. Mine is built so I can raise it up and prop a 2x4 under it to make cleaning easier, but it takes up a huge amount of room in the coop. The chickens can walk under it, but don't really seem to want to and I can't get a poop board under there that is big enough to do the job, but small enough to pull out for easy cleaning. There is also a lot of squabling for the top rung and they crowd up there and to a lesser extent on the next highest rung but won't use the bottom two at all. The other thing I don't like about mine is that I used alder saplings for the roost, I know now that 2x4's would have been better for them, but either way the design itself isn't working out well for me.
I'm putting in two 7' 2x4 roosts about 4 1/2' off the floor with a poop board about 18" below the roosts. I may adjust the height etc. a bit as I put things together, but I'm hoping that the poop board will be an easy height for me to scrape and that they'll make better use of the floor space below the roosts. The nest boxes on the end of the coop have platforms in front of each level and they use that now to get to the top roost, but I may add a ramp to the new set up as well.
It would be better if I could "see" how things go together without having to put it together first, but I don't have that talent so I tend to have to modify as I go. Wish me luck.
--I don't have any truly heavy breeds so am not as concerned about the height, but my dual purpose birds never use the ladder to get down in the morning, only to climb up at night. In the morning they all fly/flop off of the top two rungs of the ladder roost so your Brahmas may do the same thing???
We used (ugh, can never remember names of things!) The metal strapping that I think plumbers use to secure the saplings to the 2x4's , it's been up for over 1 1/2 years and nothing has shifted so it works pretty well.
ETA: I got some brackets that I'm going to use to secure the 2x4 roosts to the 2x4 frame on the new set up. I think they would work well for a 2x4 ladder roost as well so if you want I'll take pictures of them tomorrow too and/or go find my Home Depot receipt from today so I can tell you what kind of brackets they are.