The whole "you ski in the backseat thing" is not stressed enough. I can count on one hand the skiers that I know who are truly "in the front seat". More than likely, even the best instructors, coaches, and racers you know have no idea what actual access to the front of the ski feels like - let alone the general public you see when riding the chairlift. This isn't to "dis" them, but it is just not something that is taught or focused on in the proper way - ever. Really there are three components, which I think you have outlined above:
- Technique - how is the skier moving to keep themselves forward?
- Boot setup - is the boot set to the skier's physiology and actually helping them to use proper technique, or is it rewarding less than proper technique?
- Binding ramp and placement - is the binding in the correct spot on the ski if both factors above are dialed in?
Each of the above are moving targets. The goal is to be over the sweet spot of the ski while using the best possible technique... easier said than done usually. Here are some more questions to ask: When the ski is loaded and your weighted leg is mostly straight - are you hips fore or aft - and why? Where are you in relation to the sweet spot of the ski at this point? Are your hips aft because of binding placement... boot setup... technique... yes to all of the above? Not sure?
An easy way that I and several coaches I know have found to take binding placement out of the equation [and those who race on Atomic will know that Atomic has the same viewpoint because they offer ONE riveted set of holes in their black plates - that's where the bindings go - end of story - ask any Austrian coach - they will tell you]; for the most part we mount our bindings with a flat delta (@ 0 degrees), and within +/- 1cm of the BoF @ CRS mounting point (which incidentally is what Atomic does). Why? Well, basically because it is a great starting point, and usually lets you take one variable out of the equation and typically most skis tend to ski best from this mounting position if you have a good boot setup and good technique (not all though).
Second we take a measurement of the boot board angle (zeppa), and see how extreme it is. these days 3 degrees is about average, but some boots will be as high as 5-6 degrees - very heel high - others will be <1 degree - nearly flat. Boot size also plays a big role. You can adjust this internally and externally; however when you do, you also need to take dorsiflexion into consideration as you don't want to ankle lock your athlete. This takes observation both indoors with a boot fitter and on-snow. There are tons of measurements that can be taken into consideration (femur vs tibia length; torso versus leg length; overall height, etc), but I'll leave that to the boot fitters to discuss.
This brings me back to technique. This one is tough, because for most dedicated skiers, it is always evolving. What was true on day one of the season might not even apply on day 40 of the season. IMO, this is why all coaches should be trained in boot setup because a coach needs to know when it is technique holding a skier back, or if it is the boots. One example I can offer is a racer I taught a few seasons back. He had brand new boots and we were also working on a new [to him] releasing technique with him. He could execute the release perfectly, but no matter how hard he tried, he always ended up in the backseat. I sent him back to his boot fitter and had him set more upright so he could straighten his leg, and voila - no more backseat releases, and when he was extended at the apex of the turn with a loaded ski, he was right over the sweet spot of the ski. For a coach or boot fitter though, it can be tough because you can have 12 athletes, and 12 different setups depending on physiology and flexibility.
Anyway - long post - but point is that backseat skiing is not addressed enough - nor is it done in the proper ways in most cases. I prefer not to turn this into a drawn out technique thread because everyone will have a different opinion on how to bring the hips forward in relation to the skis. The only thing I will say about that is that if they don't start by talking about the feet, they ski in the backseat and don't know how to get forward.
...boot fitters... chime in.