For the most part the blood trail has to do with the location of the hit versus the type of broadhead. You will see more blood with a wider cut of course. However even a small two blade in the vital V area will produce great blood. Ranch Fairy has a good video on this.
I'm not going to click that video, but I'm assuming he is comparing blood trails with pigs?
Ever hear the term bleed like a stuck hog?
There's a reason for that. Pigs actually have a little different circulatory system then other animals. It's biased towards moving blood through the body rather than more of an even split with the pulmonary system. That's my understanding anyways. I just know they use pigs for vascular medical research and training because of the resemblance to our own circulatory system. They use sheep for reproductive research, the sheep embryos are a closer match to us.
A blood trail is dependent on where it's hit, but add in hair and other factors, hole size really starts to matter in my opinion. I have killed enough with both fixed and mechs to see a difference, with deer anyways. Never shot a pig with a bow, but I can tell you just drawing blood on them, they bleed unlike other domesticated livestock.
Everyone needs to make their own decisions on what is going to work best for them. I typically have 2-3 different heads in my quiver. Usually experimenting with a few. I have heads that I'm confident in, others that I feel aren't proven yet. When I get a perfect broadside shot on a doe I'll try an unproven (in use, they have been shot into foam plenty) head to see the results.
Any more I don't put too much faith in what someone puts in a video, or says they shoot. Plenty of TV hunters will be using an old bow, but received this year's version a week before they started hunting. They refilm a kill shot with the new bow, gotta keep sponsors happy. They are just pimping for whoever is paying them. Starting to feel the same way about promo codes for products, that makes something seem less like an endorsement and more like buy this so I get some kick back.