How to assign strength to animated object ?

My mage made an invested item in the shape of a whip.
Three effects are instilled:

  • one to make it nearly indestructible (MuAn)
  • one to give it the ability to change shape and size (MuAn)
  • one to animate it (ReAn)

The idea is to be able to use the third ability to attack enemies, immobilize them and possibly strangle them.
The attack bit will be handle with Finesse. But when it comes to holding a target and possibly strangle it, I don't know how to assign a strength.
Any idea/guidelines ?

Maybe have a look at the Unseen Porter?

Take a look at Tangle of Wood and Thorns for the grappling aspect?