Rate of Twist is not everything
Turns in however many inches is not everything. The real key is "rps" or revolutions per second.
Rate of twist combined with velocity is the key. For a given caliber, in a given barrel (fix rate of twist), a range of bullet weights and therefore lengths can be stabilized more or less by varying velocity.
When "working up a load" that is essentially what you are doing: playing with various bullets, type of powders, primers, and amount of powder to get that pefect combo for a particular barrel/action.
I have always felt that rate of twist is the dominant factor. But velocity counts, too.