Thank you very much for the questions. I've actually answered the first one a number of times, but it's a good one and definitely worth revisiting.
My approach to edged-weapon tactics is based on the idea that, if you are forced to defend yourself with a knife, it will most likely be the knife in your pocket, not the Randall in your gun safe. As such, your tactics must be based on the actual capabilities of the knife you carry and must be capable of stopping your attacker by physically incapacitating him.
With that in mind, MBC takes a hard look at human anatomy to see what targets actually stop people reliably. When it comes to thrusting--especially with minimal penetration (say three inches for a Delica)--there are very few targets that will reliably incapacitate an attacker. In general, you're talking about the central nervous system and targets that are difficult to hit in a dynamic stand-up encounter.
The Filipinos have one of the most evolved edged-weapon cultures in the world and one that has historically made very good use of small knives. One of their primary tactics is "defanging the snake"--attacking the physiological structure of the attacking limb to take away its function and disarm the attacker. Since the attacker is extending that limb toward you when he attacks, it is also a highly logical tactic.
MBC takes that tactic to a higher level and applies it against other anatomical structures that, once debilitated, severely limit your attacker's ability to harm you and provide you with an opportunity to escape. Specifically, we target the bicep/triceps and the quadriceps.
These targets are great because a small knife can literally cut them to the bone and take away critical mechanical function in an instant. The down side, however, is that they are often covered with clothing. To get to them, you must cut through that clothing. This is where edge choice comes into play.
The hardest clothing to cut through is loose cloth that moves easily over the target. If you consider typical gangbanger fashion, you have oversized, loose-fitting clothing that moves easily and hides weapons very well. To determine what edge works best, I take a "pork man" target and cover it with various types of clothing. I then cut it and quantify the results. In general terms, I've found that a good, sharp, plain-edged blade with good edge geometry consistently cuts better. Serrations often tend to "grab" the cloth and spin it with the force of the cut, dissipating the force and producing shallow cuts. Combination edges do a little better, but can still grab the cloth.
Bear in mind that these are general observations. As we all know, blades vary greatly in edge geometry and all serrations are definitely not created equal. If I had the choice of Spyderco serrations or another brand's plain-edged blade with thick, clunky edge geometry, give me the serrations!
As for question 2, I have known Craig Douglas since my days with Paladin and greatly respect his knowledge and experience. Craig's system of knife work is a great example of taking traditional Filipino tactics and adapting them to modern tactical needs. However, with all that said, Craig's needs as an undercover narcotics officer are, in my opinion, very different from the generic self-defense needs of the average person. As such, I feel that the P'Kal method is more of a "knife fighting" system than a "self-defense" system.
The basic P'Kal system comes from the Filipino art of Pekiti-Tirsia Kali. Although P'Kal/Pikal actually describes reverse or "ice-pick" grip with either edge orientation, many believe it to be exclusively an edge-in or reverse edge system. If we assume that we're taling about reverse grip, edge in, the basic "tactic" is to stab your opponent using the mechanical efficiency offered by this grip and the gross-motor-skill mechanics that support it. If he doesn't block, he gets stabbed. If he does, pull back to cut his arm with the inward-facing edge, clear the limb, and go back to stabbing.
When expressed in simple terms like this, you can see that there is very little about this that supports the concept of self-defense. More importantly, despite "sewing machine" repetitions and the other aspects of this method, much of it still relies on the idea of stabbing an attacker multiple times in the torso to stop him. If you actually analyze stabbing incidents (a big part of MBC training) and talk to people who have been stabbed, you'll find that in most cases they don't know that they have been stabbed at the time and very rarely do they stop fighting. You also need to consider that a 3-inch blade will have significantly less effect on a 300-pound biker than on a "normal" sized person.
Where P'Kal really shines is the "P'Kal Jab," which is most effective when it targets the eyes. This tactic can produce reliable, predictable stops. However, thrusting other places on the body is a very slow and inefficient way to stop an attacker. It is much more likely to result in a "long, bloody rodeo" while you hang on and wait for your attacker to succumb to the cumulative effect of the repeated thrusts. You then get to explain to the jury how you "defended" yourself by stabbing your attacker 50+ times.
I hope this helps.
Spyderco Special Projects Coordinator
Founder and Lead Instructor, Martial Blade Concepts