Don't overcomplicate regulation. It has more to do with the amount and direction the rifle moves from recoil while the bullet travels down the barrel. The faster the velocity of the bullet, the less effect adding a scope or other weight will have.

That being said, the balance point and amount of central mass makes a difference too. Two rifles weighing the same, same caliber, but one with more barrel weight, the other with better balance. The barrel heavy rifle will require more spread at the muzzel. The barrel weight will decrease rise and tourque. The more balanced rifle will rise and tourque more, therfore the muzzles will need to be closer together to compensate for this.

It's not harmonics that effect regulation as much as how much weight the rifle has and where it is in relation to the chambers. Weight behind the source of recoil ( the cartridge) will have less effect supressing rise and tourque, where weight in front of the chamber will have more effect. The reason is the sability of the push vs. pull effect. It's easier to pull a weight in a straight line than it is to push the same weight.

What makes it all so much fun ( tounge in cheek here) is that every rifle is different. Thay may act similar, but never exatly the same.