Allative of between

I would like to translate this quote into Quenya:

"Between the idea and the reality, between the motion and act, falls the shadow."

I am a bit confused by "between", for the shadow is not yet between them, but moves to the centre. Can I still use usual forms like Imbe, Enel and Mitta, or do I need an allative form of them? It seems as if we will be able to decline Imbe like a noun because it has a singular (Imbe), a plural (Imbi) and a dual form (Imbit). Might it also have an allative? Imbinna? Or what else could be used for this "between" of the quote?

Well you could paraphrase it a bit and say "to the place between the idea and reality etc." (i nómenna imbe...).

There is no attested allative form of any of the prepositions glossed as "between" however, I could imagine something like *imbena "to between" modelled on ambena "nearer to".

Ok, thanks. I think, I will choose your first suggested method. It's more unspeculative. I just hope that there is a word for place, which can be used in such an abstract way.