How much play in rear bag rest?

[LHH]

Have rear back with 2 inches between ears.
Rifle stock is a little less than 2 inches. This allows for some side to side movement compared to traditional rabbit ears that fight tightly.
Should I add material to the rear bag to make a tighter fit or is a little side to side movement tolerable?

 

[jfesi]

I would add more sand to the ears to make the rifle ride tight. You really want the rifle to track with the least amount of play as possible.