I have found that to get that rock-solid vise-grip around my feet (pain and comfort aside), I need to crank instep buckles to the three position, and then the forefoot buckles to the two position. This could only last one run due to circulatory obstruction and toe crimping, but the precision is money.
So, who does this? I have found I can ski the whole day without unbuckling with instep in two position, and forefoot in one position.
Problem is, after a protracted "pack-out" period, punching, and grinding, my once-uncomfortably-tight boots are now actually a smidgen too loose if bottom buckles aren't secured.