I've been flying a King Air for 4 years and have watched that NASA video many, many times. Beech / Raytheon / Hawker, what ever it is they call themselves this year, recommends waiting for 1/2 inch of ice to build up before you cycle the boots. If you cycle the boots four times (get two inches of build up) then the recommendation is to immediately exit the icing environment. Here is the trick. How do you determine the difference between 1/2 and 1/4 and 1 inch of ice? You guestimate based on things attached to the leading edge of the wing (stall stips, recognition light guards, etc). From what I've been told, many modern T-Props have boots that continuously cycle when you turn them on. Mine don't; they inflate and then deflate until you hit the switch again. I will say that if you hit the boots with too little ice on them, not all will pop off. In my experience, it is best to wait for a build up.

Take that NASA video to heart when it comes to tail plane icing. If you make a configuration change and things start going very bad, undo what you just did. That means keeping your hand on the flap selector until they are fully down and the aircraft is reacting normally.

One last thing. Be careful of rapid decents and level-offs with ice on the wing. Something crazy happened to me about two weeks ago, I think it was an ice induced accelerated stall because I was doing 145knots leveling off from a 2000fpm decent in a King Air, in ICM, 4000 feet above the ground, during the seconds between when I asked for the de-ice boots to be popped and the other pilot hit the switch. Scared the daylights out of me.

Happy Flying