The only thing the 'more successful ones' were doing that you weren't was to stand at a vantage point and yank the float out of the water hard at the end of the drift. With the long leaders that would have produced you some fish, garanteed.
That spot at KW bridge is infamous for the snagging techniques that take place there 24/7. I am, of course, making a blanket statement here that may not apply to some, so those who fish the KW bridge run and are ethical fisherman, please disregard this. However, the few times I have observed people fishing that run, all I saw was snagging. (hard to avoid the 's' word when KWB is in the equation).
Do not despair if you don't get into fish yet. Your approach is correct, and all it takes is some practice until you figure it out. When you fish with wool, you don't necessarily wait for the float to dip. Even the slightest hesitation, or even a light tipping of the float, may indicate that the fish is mouthing your presentation. If so, set the hook. In general, unless you are fishing bait (especially roe or egg sacks) those float don't often go under. And yes, by all means, keep that leader on the short side. It has the advantage of allowing you for a faster response when fish bite and you will not snag or floss fish.
As for the colorado blade, all you have to do is make sure you keep the blade spinning without creating much drag. It takes some practice to figure out the size and colour of the blade depending on the swiftness of the run and the conditions of the water, but you can always start with a silver number 3 and go up or down from there depending on the conditions.
Keep up the good job of going around and asking questions. Your perseverance will in time be rewarded.
Cheers,
Milo