To answer your last question...in my opinion...it doesn't matter. IF you take out the lungs. The deer probably isn't leaving earshot anyway.

I shot Bear Razorheads for approzimately 25 years. They were great. If I hit the right spot, there was a blood trail that anyone could follow. Last year, the first with a new, fast bow, I switched to mechanicals. I shot 3 deer with it, and they all were great and SHORT blood trails.

My days with mechanicals are over now. I like the blades of the Muzzy's and also the toughness of them. I'll be shooting them this year.

I also think that luck plays a little factor in a perfect blood trail. By that...you cannot have some chunk of innard block the low hole on the animal...as that will impede bleeding.