Twist Rate for the 6.5 mm Custom Barrel and Over Twist Problem

[alberta.elk]

Hello All,
I want to shoot Hammer Bullet - 137 Grain Hammer Hunter and Hammer bullet company recommended the 1:6.5" twist rate.
If I use the 1:6.5 Twist rate barrel for lighter bullet (not the lightest bullet), will I get the Over Twist ?

If yes, what is the all around twist rate for 6.5 mm caliber (6.5 Creedmoor) that can shoot the heaviest and heavy bullets?


Thanks