That sound like it will look nice. if you are using the Atlas switches, the #5's will give about a 4" center to center spacing. If you are using Ross, they have a transition piece that can get you a 3.5 center to center spacing of a #4 or #5 ladder.
The ties will be pretty close? What's the width of the Atlas tie?
That can be 120" to 130" long and 24" wide.