I was surprised that someone would be looking for jet stix - this brings back a flood of memories.
Interestingly, this stance on skis started with Jean-Claude Killy during a World Cup race he won. Skiers saw him sitting back at one point in the race and the skis jetting out in front after he went off a bump, and it suddenly became the hot new way to ski.
In fact, I remember trying it myself, and later seeing some top-of-the-line yellow "banana" boots with a really high cuff that allowed the skier to sit back just like Killy did.
The irony of it all was that Killy was later interviewed about this startling new technique and he sheepishly admitted that he had just lost his balance and was just trying to recover! He claimed he had not intended to ski that way at all. However, for some reason, this interview apparently was not published widely and so the myth continued for some time. It seemed at the time to add to his stature as a World Cup skier and enhance his product promotions and endorsements.
In the same vein, a classic Lange boot poster was published shortly after with a sexy girl in a one-piece ski suit unzippered to the navel with her breasts exposed jetting off a mogul, with a caption something like " Keep those tips up!". Copies of this poster are currently available on ebay.
I remember those Rosemount boots - short, stubby and built like a tank - they even had a large SS plate bolted on the inside ankle to protect the boot from the other ski edge, because in those days, the proper ski technique was to ski with both skis completely together which inevitably sliced up the boot shells at each inner ankle, and in the process, provided clear evidence of an advanced skier!
Anyway, today the proper stance and balance is to have your weight centred through your boots, and not sit back with your centre of mass behind your boots.
Modern boots tend to be softer in forward flex since modern shaped skis do not require the massive pressure to carve that was needed to flex the older, straight skis. Modern boots, however, are stiff laterally, to facilitate hard angulation and the high G-forces of carving.
Bottom line - put those Rosemounts up on the mantel for "show and tell" and buy new boots.