I like the current setup very much...and it looks like you may have fewer nest box battles with the 2 nesting areas. Doubting that roosting together will work for space, pecking order all in one of the structures. They need space to stretch and flap wings inside, and it can get very warm with a bunch of bodies camping in one small structure. If it ain't broke, maybe don't fix it, except to remove or make an adjustment to the dividing screen so they can choose to explore the other areas? Adding more perches (that don't attract red mites) would be enjoyed by all. Sawhorses from the garage work great for our flock.