Riflemen veterancy does absolutely nothing to increase their durability versus AOE. These test results are pure RNG.
Grens do get better resistance versus AOE with vet 3, but since tank shells deal 160 damage it won't help against the near AOE damage oneshotting models.
Received accuracy also practically does not matter against scatter weapons (tank main gun versus infantry). The chance to directly hit a model is 2-5% based on the distance, so that's negligible. Tanks use scatter to hit infantry, which is a random RNG calculation that totally ignores infantry target size.
You know what i'll do some more test and get back to you.
I'm gonna do this,
Wanna give me any particular test you wanna suggest to me.