Increasing NPC size

I managed to increase some NPCs’ size clientside, but it doesn’t work on every NPC.
That’s just a bit of a problem, main thing is that I have no idea how to increase its size serverside as well to increase its hitboxes. I’ve tried SetCollisionBounds() and PhysicsInitBox() but none of them worked (PhysicsInitBox() made it crash too probably trying to apply physics on NPC)