Old Grump, cheating is good. Among several of my favorite Murphy's Laws of Combat is the one that says, "If you find yourself in a fair fight, your tactics suck."
As far as the 10" Bowie vs a smaller knife, it depends on training. It only requires 2.5" - 3" to reach vitals, if the knife is placed well; so, a knife in the 4" to 7" range can be every bit as effective as a Bowie, depending on how it is used, without the drawbacks that come with mass and length. OTOH, the Bowie's shape and weight lend themselves better toward slashing. IIRC some things I read on Bowie, he liked to get inside and use his blade slashing against legs, or else stabbing up into the gut - and he successfully used it in duels against guys who were wielding swords.
Note that the Roman gladius was "only" about 18" long; for the Romans' massed tactics, anything longer would have been unwieldy. In the Roman shield wall, the gladius would typically be used to go after femoral arteries, groins, and guts, stabbing inward or upward from below shield level. Bowie, from what I read, used the large knife in much the way the Romans used the short sword.
Tactics can dictate the weapon; to an extent, the weapon may also dictate tactics.
I know one MP who likes to use a karambit knife in his off hand. His idea being that if somebody tries to grab his gun, he can use his off hand to draw his karambit and slash across the hand/wrist of the grabber. His retention training involves use of the karambit in that fashion; he has a training version made out of some sort of plastic, looks like lexan, that he uses when practicing.
On a similar note, he and I have blue guns that we use in our real guns' holsters when we practice this kind of thing. (I am NOT an MP; this is a guy who used to train at the same dojo as I did, and we would work out on other stuff before or after the formal class.)