The bindings placement is an important element of Fore-aft alignment, together with the Ski boot setup, so let's take a look at some thoughts on where to set the bindings. It will impact your carving ability and overall skiing.
In setting the bindings, these concepts are relevant:
BoF Ball of foot
CRS Center of Running Surface - the center point between the contact points of the base with the snow/floor
Middle mark most skis and boots have a middle mark, where the manufacturers think they should be placed (so that the mark on the boot aligns with the mark on the ski).
Also, the Ski feedback is an important element in fine-tuning a ski.
The basic setting is aligning the middle marks on the skis and boots, to get the manufacturer's intended feel of the skis.
Some argue that this method (BoF over CRS) is placing them too far back, as the manufacturers try to make it easy for unskilled skiers to skid instead of carve and all carvers should move them forward, see articles below.
Technique is certainly a big consideration when choosing this position, but don't forget that it also depends on the skis... park skis like to be ridden i a more central position, for better neutral balance when rotating in the air for instance.
We will focus on "piste" skis, with a look to performance and carving.
At the higher performance end of skiing, the common practice seems to be to match the BoF with the CRS. The basic idea is that good skiers can get forward and bend the ski nicely into a carve and this would yield the best use of the ski and the best response. Some manufacturers may muddy this a bit with varying ski construction (i.e. a softer tip or a square tail) but these variations go more towards how the skis perform at different places in the turn (better initiation or a more powerful exit).
I love Atomic bindings, since most are very adjustable, some even tool-less. the X Race bindings have one tab that you can use to set it in one of no less than 8 positions, from far forward to far back, about one inch each way.
When you set the bindings more forward, the feeling in the beginning is that of overpowering the tips of the skis and having no feeling for the tail, which we will hate in the beginning. You loose power out of the turns.
When you move them far back, the ski becomes harder to turn... you do get more power from the tails, of course, but lose some feel for the tips.
So... going a few times back and forth until I left them slightly forward and now I’m happy at about quarter inch forward. That seems to be my sweetspot in GS. In SL, more central feels better.
Also, this will vary based on individual preferences and even conditions.
Next time you demo some skis, you should ask the rep there to move the bindings for you, sometimes the demo bindings are easy to move.
Don't use the bindings position to compensate for other fore-aft issues. The boots are the first to look at when you have fore/aft issues, then technique and the skis are last.
Skiing with the boots undone++ is a good way to improve and figure out your fore/aft.
Moving from a larger boot to a smaller boot (i.e. from a 295mm to a 285mm) will effectively move you forward by half the difference (5mm in the example) and vice versa... so you may have to remount the bindings, when changing boots, if the difference in behaviour is too big.
Before we close this subject, let's look at some of the issues surrounding the binding mounting position.
Type of ski I have a twin tip, which is mounted very central, maybe 3 inches forward of a normal all-mountain or on-piste mount. The reason is that this is best for doing tricks and spins, to feel the ski balanced. Basically, this is not mounted to be skied on, but to do tricks on!
So do take the intended use of the ski into account! Here, we'll focus on mounting skis meant to be skied and specifically I think, on-piste!
Self-steering if the skier's weight is behind the middle of the ski, then when the skier stands on the ski and puts it slightly on edge, the ski will start to skid and turn. This is "self-steering" effect is a reason why the bindings are mounted aft of the middle of the ski.
Also, if you look at most sidecut skis, the narrowest point is behind the CRS, so if we mount BoF over CRS, the skier will usually apply pressure in front of the narrowest part of the ski! This will help in bending the tip of the ski more and establish the carve and it's more helpful than bending the aft part of the ski!
Interesting notes and articles on setting the bindings with a forward bias, if you have the time:
[...] the World Cup level skis are often tested starting with a ball-of-foot (BOF)/crs mount. [...] our results over the years have shown that a BOF/CRS mount works well on nearly all skis in all conditions.
Note that generally racers are set forward 1-3cm in general. And the good ones test all positions until they find what they like.
Also, look at the tables there: most skis are marked back 1-3 cm by the manufacturers…
What the research team saw with their own coaches' eyes was that every skier in the diverse group skied better in the forward position, with no other variables of any kind.