Very few of the settings that can be applied require a service restart. ASW lock, supersampling, and FOV multiplier do not need service restarts. If you don’t believe me, turn on the overlays I mentioned above and take a look at the ones relevant to each of these settings while you change them.
The only settings in the Tray Tool or Debug Tool that require restart of the Oculus service are the render resolution settings specific to Link.
Supersampling settings, when used with Link, typically need the VR app to be restarted, but not the Oculus service nor Oculus app. Again, you can confirm this with the Pixel Density HUD overlay.
When setting the FOV crop values in the Tray Tool, you have to click the button to the right of them (I think it says save or apply) for them to be sent as commands. And yes, almost everything the Tray Tool (and Debug Tool) do are indeed one-shot text string commands to the runtime. They are just sinple GUIs which send those commands for you. Every single setting that you can change related to the runtime in either of those tools are also available at the command line of the CLI debug tool. Typing server:help (I think that’s it, going off of memory here) in the CLI debug tool will list every user-settable command available.
ASW behaves strangely in general with Link and MSFS due to a frametiming conflict. You have to open the Nvidia driver settings and, in the app-specific profile for MSFS, set v-sync to ‘Fast.’ If you don’t do this, then the app frame rate fluctuates to such an extent that ASW never actually locks even if you command it to, and if you disable ASW entirely it will be unable to reach the full refresh frame rate regardless of available headroom unless V-Sync is set to ‘Fast.’