Bee,
I'm with Wilson and Ted on this. You shouldn't even be trying to get a knee down on public streets. That's an accident waiting to happen. Save knee-dragging for the track. Once you're on the track, focus on body position, speed, and race line rather than getting your knee down. It will happen all on its own when you're doing things right. If you try too hard to get a knee down before you've mastered correct body position and throttle control, you're flirting with a high-side.
Btw, dragging your knee is not about maximizing lean angle. In fact, it's about the opposite. By getting off the bike, you lower your center of gravity while keeping the bike more upright. This allows you to get on the gas harder and sooner than if you were on top of the bike and leaned over more. Check out the pic below, (Turn 4 at Thunderbolt, the chicane): Look how low my body is. If instead of hangin' off, I was seated on top of the bike, with my center of gravity much higher, I'd be carrying much more centrifical force into the corner, and I'd have to lean much more in order to counteract that increased centrifical force if I wanted to carry the same speed. And since I'm already close to maximum safe lean angle, that wouldn't be possible. Lean angle being constant, if you lower your center of gravity, you reduce outward force pushing you off the line, and can corner faster for any given lean angle. Conversely, for any given corner speed, reduce your center of gravity, and you can reduce lean angle. Either way, you're cornering faster. It's all physics.
Go to the track and focus on basics. It'll come to you when you're ready.
Elton