I've stayed out of this one for 10 pages, but I gotta chime in.
Putting this much thought and effort into building arrows is a little silly in my mind. It's good to see guys thinking about their setups and how they're tuned, but my experience is that almost any arrow/broadhead combo will kill deer with boring predictability as long as the bow is tuned and the archer has his act together.
I've shot end-of-season clearance arrows/heads for years. That means I've shot "twizzlers and flappers" and "telephone poles and spear tips." Whatever was cheap. I've also had the dubious privilege of listening to many, MANY stories of unsuccessful shots and recoveries. I don't know that a customer ever walked up to the counter with his setup after losing a deer and the conculsion was, "Man, you need more FOC." Usually it was a bow that was pathetically out of tune or (more often) a shooter that shot a lot better in his head than he did in the range. All of my personal sob stories are the results of malfunctions in the onboard targeting computer.
Take almost any broadhead/arrow/bow off of the wall at your local sporting goods store today, set it up correctly, and place an arrow below the spine, above the brisket, behind the shoulder, and forward of the diaphragm of any whitetail inside of 40 yards and the results are quite predictable. Deer are easy to kill.
I agree there is a peace-of-mind factor to a heavier setup and a robust, COC head if you're worried about a shoulder. There's also a little peace-of-mind factor to be gained from a lighter arrow if you're worried about the difference between a 35 and a 40 yard shot. But most of this is in your head more than it is in the field.
The same marketing geniuses that convinced folks they needed a 2.5" wide expandable are now convincing folks they need a 300 grain COC. If you want it, cool. You don't need it, and the guy reading this don't need it. Chances are you need to shoot more deer and exorcise your inner bowhunter demons. That's hard to do while you're at work or on the couch though.
Same thing that holds for arrows holds for bullets. I've killed (and lost) deer with 80 grain pills and 450 grain slugs. Light and fast, heavy and slow...it probably don't matter to most of the hunters shooting most of the deer.
I have nothing against Dr. Ashby or the fairies, aside from the fact that they seem to be a bandwagon. But hey, I saddlehunt.
I do get irritated by folks assuming buying and using gear will solve a problem (jaded tech for sure.) Guarantee that the folks who are switching to heavier setups because they plugged a shoulder or didn't have their bow setup correctly and got poor penetration as a result are gonna be switching back to lighter rigs the first time they shoot under a belly or have a deer duck their "slow" arrow.
Buy a heavy arrow. Buy a light arrow. Just so long as you LEARN to tune a bow, LEARN to judge distance, LEARN to read a deer's body language, LEARN to identify questionable shots, LEARN to control the jitters, LEARN to blood trail, and most importantly LEARN that you are going to lose deer. I'd love to see a thread grow to 10 pages this quickly on any of those topics, but for whatever reason gear threads always get more traffic than skill threads. Not pointing fingers, I'm a puppet of consumerism too.
I killed 13 big-game critters this year. Nary a miss or a lost animal. 2 years ago I lost 3 deer and a hog in one season. Stuff happens. You can shoot a 300 RUM "just in case" and still lay awake at night wondering what happened.