How high for a horizontal roost?

[09northernchick]

My 5 week old babies will hopefully be going to the coop this weekend!!! I will be putting their roost in tomorrow. I had been planning on placing it about 26" from the floor. But there is a window immediately above where the roost will be and I think they would like to look out the window. How high can I safely place a horizontal style roost so that they don't hurt themselves getting up or down? They are standard size birds, or will be

 

[DarkWolf]

Mine are 32" off the ground and they have two windows to look out.. Finished it this morning.. They love it and more often than not are by the windows. They're 7 and 8 weeks old and handle the jump fine.. 2" of litter.