I've had nest boxes in three different spots in the coop and they just find the ones they want and use them, no matter which way the nests face. I have 6 (now - before I had 5) nest boxes and 28 chickens, most of which are laying regularly. Still waiting for the Buff Brahmas to get old enough to lay. I haven't found that the direction of the nests makes a bit of difference. They explore, decide, and then lay.
Three of our nests are up and 3 are down at coop floor level. They use them all, uppers and lowers. Personally I hate the lower ones - hard for this old body to get down to pull eggs from them. But it was the only arrangement that would work in our coop.
I'm not sure how you are going to do the roost up higher, but may I make a suggestion? Since you are changing things anyway, can you flip the roost over so that the widest side of the 2x4 is facing up? Chickens seem to do better with a wider surface to roost on rather than curl their feet.