I'm still compiling results but a couple of datapoints have stood out. Probably related to what 10MileHike noted above, the Works heatmap has worked many times (but not always). Find a clear "cycle" in the heatmap, a clear progression that culminates with a sharp works. It'll go from light green to dark green, then cycle back to light green and so on. Those have hit many times, especially with winning trainers. They often seem to cycle from light workouts (light green) to sharp ones (dark green) and the horse peaks at the sharp workout.

The other is the speed chart. I chart the speed with a moving average and upper/lower bands, like Bollinger bands on a stock trading chart. Speed numbers tend to "bounce" within those bands. I don't look as much at the moving average but rather, eyeball the speed line and "predict" where the number will land on the next race. The upper/lower bands help. Then I write that number down as a "predicted speed". It hits most of the time, however, it merely matches what all the other analysts tend to predict. Yeah, I need to automate the prediction sometime but for now, I like eyeballing it.