Take a step back before you begin filling in with more roses. I plan to add a contrast with carnations later - so I although I want the roses to be the focal flowers, I don't want a tight pack design that doesn't leave room for the miniature carnations.
I'm placing another rose on the right hand side.
Here is a side view of the right of the rose bouquet.
See the final placement and direction of this rose.
I placed a rose in the upper left of the bouquet.
Here is a diagram of the insertions and placement of the roses.