Technique is coached and agility can be improved if you have smooth hips but lacking raw speed is lacking raw speed. To believe you can gauge playing speed based on playing versus random high school talent is ridiculous although production and film can give you an idea on consistency.
In high school, you have kids playing versus 190-pound linemen and the majority of running backs, receivers, linebackers and defensive backs can't even break a 5 flat in the 40. Most quarterbacks lack great arm strength and quality coaching.
College sports weeds out 99.9 percent of the player you will face in high school leaving generally that fastest, biggest, strongest and most athletic to compete against each other. The majority of the .1% that moves on will never be a starter.
In the modern internet age allows you to weed out the real speed versus high school speed with tons of information available to choose the right guys.
Character, passion, academic integrity and determination are things you can't gauge without talking to others about a player but if you aren't building around real speed, you will find yourself quite a few steps behind on the football field giving up 50 points per gameSenior game film or in person evaluation is usually the primary recruiting tool of seniors as highlights will rarely give you a good base to evaluate a prospect.
You also have to consider the factor of overall team factors such as team depth and size versus opponents which can make solid player look much better than his individual talent.
