Another Hammer arrestor question

I'm installing a new shower thermostatic valve and 1/4 turn volume control.

The old mixing valve had air chambers on the hot and cold inlets. Now that I have separate valves for temp and volume where ideally should the arrestor be placed? 1 arrestor on each hot and cold inlet or 1 at the volume control?

arrestors

The "water hammer" will occur at the volume control, but putting the arrestors on the hot and cold lines to the valve should minimize the problem