Their is simple to much theory crafting to be honest...
"remember a VG with shrek and vet 4 has less AI then a vanilla gren squad..."
Use a mirror please. I'm still waiting for that replay were you show us your skills.
Grens 20.81/10.44/7.87
Vet4 Volks with shrecks** 22.15/11.32/8.25*
#Mathplz
Vet3 Gren: 29.14/14.62/11.02*
Vet4 Volks (no shrecks)*: 27.68/14.15/10.31*
Vet3 Cons: 25.10/12.78/6.16
*I didn't take into account the cooldown bonus.
**Shrecks tend to add a HUGE RNG DPS.
Why did i add the cons? Because bananas for scale.
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"The raketenwerfer as an at gun is underperforming just as hard as volksgrenadiers with panzershrecks are overperforming, so that's something to keep in mind."
Basically this.
Eventhough my POV is that theres no easy elegant solution for the problem.