That is a very large room in the center of the map. Aliens would need a bit of cover there or else they'll get slaughtered. Each hive should get an rt, plus some of the larger rooms. But I'll leave the exact placement up to you.
The map looks too flat to me. But maybe that's just because of the angle in which the screenshot was taken. Using height means more fun maps.
I think this pic I made for you (in paint) will say the rest: