First of all, you must realize that your intended sense of
strategic(ally) is actually a metaphorical one: the word's literal sense is military, relating to the conduct of war. For example, the OED
gives the following two definitions of
strategically:
1. In a manner consistent with the principles of military strategy; as regards military strategy.
2. In a manner that is useful or important in relation to an overall plan or design. Also: in a skilfully planned or executed manner.
In regards to the second, transferative sense (yours), Collins
says:
If you put something in a strategic position, you place it cleverly in a position where it will be most useful or have the most effect.
So there is an idea of usefulness, of skill or cleverness, of efficacy, and - crucially - of alignment with some kind of larger plan. You will be hard pressed to find closer English synonyms than
apt(ly),
fitting(ly),
convenient(ly),
artful(ly),
shrewd(ly), etc.
Thus, to translate the English word
usefully, Smith and Hall
suggests the Latin words
utiliter,
commode, and
apte. If you desire a stronger connotation of shrewdness or calculation, you could say
callide or
astute. But you are certainly not going to be able to replicate the precise nuance that the English word inherits from its primary, military sense. Indeed, under the headword
strategically, Smith and Hall
offers only the paraphase:
*quod ad belli rationes attinet [= that which appertains to the methods of war].
As regards the English
insertion, there is no strictly equivalent Latin
noun; rather, in Latin, one would most naturally express this idea by means of a verb. Hence my suggestion of the participle
interposita (lit. placed between or into).