Laying out certian geometry has always been a little dificult in Revit. For instance: octagon bays. You need a lot of dimensions and ref. lines and then when you change your mind on the design you can't just scale the bay.
I've made a series of helpers. Each helper is a geometric figure with an instanced parameter. Now I can just stretch it to the size I want. Then I can use the align tool to attach the walls in the right spot....