I suppose what I need to know is how to re-alias these setttings - what exactly to write and where, or the mastercomfig values for the default snapshot_buffer i.e. what interp value does snapshot_buffer_low (projectile) have? It doesn't say. snapshot_buffer=safe (hitscan) has 30ms of interp so that would be cl_interp 0.030. I could just use custom snapshot buffer and then put these default values in every class config except spy, but if someone could tell me how to re-alias the settings in the module that would be really nice and less cluttered.

How do I change the interp setting of only ONE class while using mastercomfig? I want to change the network settings for when I play spy, but the default mastercomfig settings are fine for the other classes. How do I proceed?

If I use the module snapshot_buffer=custom all the other classes are affected.
I do not quite grasp how to use Network Aliases:

Network Aliases¶
These aliases are used by mastercomfig to apply network settings per class (as listed below) when using the snapshot_buffer=auto module level.

You can run them manually in your class config if you play a subclass, like Demoknight (net_hitscan) or Huntsman (net_projectiles).

You can also re-alias them to use your own network settings.

net_projectiles: Alias for network settings on projectile classes (Soldier, Pyro, Demoman, Medic) (snapshot_buffer_low).
net_hitscan: Alias for network settings on hitscan classes (Scout, Heavy, Engineer, Sniper) (snapshot_buffer_safe).
net_spy: Alias for network settings on Spy (snapshot_buffer_safe).

How does this work? I put net_spy in /cfg/overrides/spy.cfg and then what? net_spy cl_interp x?