I'm so glad that I could write something that could kick-start your own creative thoughts. (Almost said 'juices' there, but that would have been naughty!!)
I can see that you have grasped the concept, and have plans on how to implement it.
I wish you and her lots of fun with implementing the plan!
PS. I can understand why she doesn't want a safe-word yet, because Just the presence of one implies the possibility of it being used.
She will learn that she can trust you, even when it seems like you are planning on pushing her... That isn't the type and depth of trust easily given to another... Not even a spouse.
xxx