There was 14 - 20 inches of fresh today and I took out my new 150s, which I skied in for about 10 years previously before going to a softer boot. I barely buckled the top and skied better than I have in two years . A good portion of that was fit to my feet, ankle and lower leg, but the stiffness is what did it. I could use very small moves in my feet and ankles to BALANCE. The pressure on my shin came from the skis turning, not me pushing on my boot. By the end of the day it was two below, my boots were probably a 160+ and it had little effect on my skiing.
BTW - The lift your toes thing is not something I think about, but It can be a good tip for someone that has the proper equipment setup but is having problems with fore/aft in powder. Not everything works for everyone. Remember the CAP model?
TDK, I thought about your question today about why we use booster straps. For me, it was simply to hold the tounge of the liner in the place it needs to be in my boot so my feet, ankle and lower leg move properly. With the crappy stock velcro strap on (which moved and loosened), the toung of my boot would rise up a little to high or move to one side of my leg or another. When it moved up due to my high instep or to the side from lateral pressure it sent big changes up the body. Maybe that's why I like a stiff boot like that, because I know when it is me not balanced or my boots. The soft boot I demoed for a learning experience a few days ago was OK at slow speeds and on groomed, but when I started skiing faster in terrain it was down right scary to me. Every move I made seemed late and instead of skiing with my feet and feeling the mechanics go up from there, I felt like I was constantly compensating with my body.
To whoever said, "Why don't we ski in a boot that only comes up over your ankle? As far as fore/aft pressure goes, I think I would prefer that (short cuff) but when I was tipped and rotating (and airs) I could feel the need for the boot to be higher on the side for lateral pressure.
The wrong boots completely screwed up my skiing for the last two years. I'm so happy to be back in business. The tipping and leg rotation was easy because I was balanced.