I would have thought the latter.
Reforge plots make sense, change in deltas of your stat weights before proc will change (either significantly or trivially depending on where the delta is and how large) how the proc effects you at the point of proc.
Stat weight deltas, which I'm assuming you mean to the weight we place upon the stat, should not effect the behaviour of the trinket but will change how we decide to act upon it.
That is, the behaviour of the trinket is independent of the value we place upon the stats.
Forgive me, but this seems obvious, so am I misunderstanding you here?
Do you mean the delta that occurs in our stats during the proc? For example, if we procced it in such a way as to give us haste, that should effect the behaviour of the trinket