67 Barracuda Fastback Lid Adjust

Clementine- don’t you mean lowering the latch mechanism a tad bit will make the trunk lid close tighter?

If you raise it- you are allowing it to latch further up. Unless I’m missing something here.

And I agree on the weatherstrip.
If shot it may never stop rattling.
Typically I found just replacing the weather strip and not touching the latch will correct most rattles in that case.