It's my understanding that the archers were the snipers of their day - real professionals who took great pride in their skills, acquired only after at least 10 years of constant daily practice, which developed their muscles grotesquely. They made their own bows, so almost certainly would make them as powerful as they could handle. The arrows were supplied and were packed in barrels, carried on carts, so were fairly standard. Certainly, the bodkin heads had the greatest penetration potential, the broad heads were almost impossible to remove, and were seen as a deadlier weapon because the wound would almost certainly become infected, but from what I've read that didn't make much difference, because almost all penetrating wounds would carry bacteria from clothing into the wound, so most wounds would end up fatal over time.
The arrows were probably over-weight, the thinking at the time being that heavier arrows hit harder, and so they do - if you double the weight of a projectile then it hits twice as hard - but modern understanding of physics tells us that if you go the other way, reduce the weight and double the speed, it hits 4x as hard.
From what I've read, even the much smaller and lighter bows of Native American Indians (designed for use whilst riding cantering horses) were proved to penetrate the invading Spaniard's armour at 100 paces