There was an excellent discussion of this topic on Blarp in August:http://blarp.com:8080/read?3568,14e#3568
posts #14 to #19 in that thread. If you have problems accessing that thread, first enter Blarp as a guest, and then do a keyword search on the terms "center pressure area" and that thread should pop up.
To summarize that discussion, there are a huge number of important "centers" on a ski. These include, the center of load bearing area, the fore-aft position of the sidecut waist, the chord center, the running surface center, the center of mass, etc. These various locations can be quite a few cm away from each other.
Ski designers try to come to a compromise amongst all of these when they decide on a suggested binding location. They do this based on previous experience and on-hill testing for each new ski model.
Often, the old rule of positioning the boot toe at the chord center comes out fairly close to the mfgr's recommended location (but usually, only for men with average length feet). "Boot center" locating marks are a way to circumvent foot length variability and other difficulties.
Eventually, if you could tinker with your binding position, you might decide that you don't like the compromise that the designers settled on, but, except in very unusual cases, it certainly is the best place to start.
If you have an unusual physique (eg, a huge beer belly, or butt) AND you know from lots of previous experience in mounting and moving bindings that a little forward or backward from the suggested location almost always works better for you, then start there, but if you already knew that information, I don't think you would be asking this question.
It's great fun to tinker with the location using bindings that can be adjusted fore and aft with out remounting each time you try a new location. The old Atomic ESSvar and newer Xentrix's can do this as well as number of other more obscure ones.
Hope this helped.
Tom / PM
<FONT COLOR="#800080" SIZE="1">[ November 07, 2001 07:13 PM: Message edited 1 time, by PhysicsMan ]</font>