I determine the most accurate pellet for my gun, then 49 times out of 50 I make a headshot between the ear and eye on a groundhog or squirrel and it doesn't matter which pellet I use. I have used polymags in my .25 Marauder but in truth I see no terminal differences between that or a standard JSB pellet when I take a well placed shot. The other 1 time out of 50 I might take a heart\lung shot on a squirrel if the shot only allows that, but I make sure I have a clear heart/lung sight picture. In all cases I only care about 1" of penetration to scramble that brain. Squirrels I usually get a pass-thru in the head unless I'm using a sub 12 ft-lb gun, but it was that first 1/2" that mattered. In groundhogs I never get an exit wound even with 55 ft-lbs Marauder pushing it only 1" to 1 1/4" into the head. In all cases it is the shot placement stopping them, not the wound channel causing collateral damage.
The only time I see the need to evaluate if a pellet penetrates 3" of potato is if you plan to gut shoot some animal enter mass and you are looking for a wound channel to make up for poor shot placement. I think the time would be best spent determining the most accurate pellet for the distances you plan to hunt. If you luck out and find 2 or 3 pellets are equally as accurate, only then give some consideration to which might have the most terminal performance. Again, the groundhogs I shoot never know the difference between a fancy polymag and a round head pellet.
If you pick a hollowpoint based upon expected wound channel, but that pellet doesn't group well, then that pellet likely isn't hitting the animal where you want to hit it. These types of 'ballistic' experiments frequently appear in gun magazines and youtube videos, often for handgun ammo. In those cases wound channel is relevant as folks are generally shooting center mass in a hurry and need all the help they can get subduing a bad guy. But trust me, if they had the time to take a well placed shot like an ethical hunter should be doing, even ball ammo sent into that juicy brain is going to have devastating effects.