Well.....my idea isn't working. I used 2x4 on edge, about a foot in front and a few inches higher than the nest lip and they still prefer the nest boxes or front lip to roost. I'm using a nest box/feed hanger design which may make the perches too high. I added a 5 gal bucket with vertical nipples but even as high as I could hang it isn't really high enough for them to drink comfortably. They have to squat a bit and crane their necks.
If the perches are as high as the nest boxes, they're not too high. My birds roost in the rafters.
How large is your coop?