I view CoM as basically the same thing as picking something specific, you are still aiming for a small point in the center of the target rather than at the entire target. Same mental effect, I would think.
And for the mongolian stuff, check on google or wikipedia, and you'll find some stuff. Personally, I like the english style (1 finger over, 2 below), but it's a little wierd on your wrist( hand is used to being horizantal at that position, rather than vertical).
This is the best video of mongolian style arching I could find on short notice. He shows how they string it, how they nock, draw, and release, and then gives a quick action shot, and then a really quick action shot.
http://www.youtube.com/watch?v=Bn9TsKzC ... ed&search=
Here's a video of Japanese style that kind of explains something that is still going today.
http://www.youtube.com/watch?v=InKmjTJz ... ed&search=
Looks like the same people did a few other martial arts episodes on escrima and stuff, kinda cool.
Anyway, back on topic a bit.
I don't think there is one "best" way to draw the string, just what you are comfortable with. Most of the asian draws though, seem to go back past your ear, so unless you are short, it won't work for belegarth. I like the style that I used because you are looking along the arrow, from (supposed to be) directly above the arrow, so if you can get it aligned left and right on a stationary target, all you have to worry about is distance, windage, and leading.
And about the different types of bows. I'd love to get a mongolian bow for belegarth eventually, but as they are expensive, I'll wait a while for it. There is a dagorhir unit that has several people with the bows (mongolian steppe unit) called the Kutriguri. Also, there is a Japanese themed unit that has been there at Rag the last 3 years, and one of them had a Yuni-ish bow (proportioned correctly limbs, though I doubt using the traditional materials).
Overall though. the style of bow doesn't really matter too much either. You just want one close to 35# with a smooth draw. A longer bow (limb tip to limb tip) generally gives more forgiveness and strength at the same poundage as a shorter bow, but it comes at the price of decreased maneuverability. The mongolian bows are able to somewhat get around this due to the short brace height(distance from handle to string when bow is at rest), geometry of the limbs, and materials of the limbs. However, I doubt that they were more powerful than the english longbows, I'll have to check up on it.