Here is the big secret to dragging your knee......go faster it will happen.
To have it happen faster, body positioning comes into play. The rider above from Summit point appears to have his head up high over the windscreen. You want to really lock in your body and get your chest leaning on the edge of the tank and get your head on the side of the windscreen. You want your upper body to line up with your lower body. Many riders will shift a cheek off the bike but keep their upper body centered in respect to the windscreen. This makes for a high center of gravity, plus by doing this your knee will have further to go to touch the ground. Sit on your bike and sit straight up and put your knee out, look how far it is from the ground. Lets say you are making a right turn...Slide 1 cheek onto the side of the seat, take your left foot and stand on the balls of your feet, lock in your heal to the heal guard, keep your left leg tight on the tank, lock your left knee in, keep your ass back in the seat or better get leverage by putting your ass against the back of the seat(this will also make the next item easier), rest your chest on the edge of the tank, keep your left arm around the edge of the tank(if comfortable you can rest that elbow on the tank), get your head on the right side of the wind screen, lock your right heel into the heel guard, put your right toe on the edge of the peg and keep your right sholder facing down towards the asphalt. You want your shoulders to line up with your where your butt is. Locking all these bodyparts in will allow you to be feather light on the bars and lay across the bike while keeping a very low center of gravity, also it will get your knee closer to the ground.
Oh yeah did I say go faster? That will help. Once you drag your knee once it is easy to keep doing it, then a day will come where you wish it wasn't dragging so much because your running through knee pucks on a regular basis. Especially at Jennings, that track seems to be the coarsest I've run on and went through 1/2 a set of pucks in a day.
Z
