Tim,
I am going to assume nobody is going to address your "target " questions. I will try to take them one by one, if I miss something let me know.
The size and blade geometry in a defense knife is
very important. I regularly wear a 14"oal Ishtar made by Dervish Knives. It is
all slash, it would take out an arm, or cut through a rib cage, or reach a carotid on the first pass, because of is size and blade design, with some of the fighting style I use, a knife becomes an arm velocity accelerator, like a flyswatter. With one of the knives I wear, an RJ Martin 5" Kwaiken, The fulcrum of the tip will part flesh, etc very quickly, and is very capable of piercing the skull, or body armour.
When a body is under stress of extreme survival, several uncontrollable biological things happen, small motor sklls and untrained "moves" can't be found...a conventional blade with good to excellent blade geometry will be delivered in a natural, or hammer grip, and weilded by your ancestral instincts...
translation...make sure it it sharp, big enough to deliver lethal strikes, and keep the design simple,
no moving parts. Slashing targets are used in combination with finishing thrusts. one "complete " slashing target involves a technique that diarticulates the liver, another "defangs the snake" in the event of a grasping or choking attack, by cutting all of the tendons and connective tissues in the hand or forearm; slashing the femoral artery will cause unconciousness quicker that some handgun wounds would.
Whatever style you decide on remember this: knife cuts are immediately and acutely
painful, often causing an attacker to rethink his bright idea to attack you, but you have to remember
simplicity is the key, the very definition of self defense means that you are already under attack, and behind the 8-ball. Get some good tapes ofdifferent styles, Kelly Worden, and James Keating being the most comprehensive. Keating offers camps for trainng if you are up to it, but you have to practice your style to keep your
fighting brain trained.
I am being factual, if not somewhat technical here, I hope I have not offended any one. Tim, if this turns out not to bewhat you want, that's ok, it's not for everyone.
.