Hope my post didn't bother you. Mid 70s isn't bad at all, upper 70s is good and 80 or better is outstanding. Arm strength can be improved with age and work. 80 or better is far from impossible. If he has quick feet and quick release with some accuracy, he has a chance to play most anywhere. If he can hit, run and receive, he can play at a high level. Remember that many players develop a lot while they are in college.
I agree with you about hand held times. We usually have at least three timers. Most all the time they are within a tenth, but not always. Truth is I like the eye test better. The guys that can really catch and throw just standout, you don't need a time or radar gun reading to pick those guys out. But others that aren't there to see it, want to know the numbers.
I agree with PGStaff. My velocity 2 years ago was 75. I am not sure what it is now. I have quick feet, and I am accurate. I also am able to block and receive. Would the other assets besides pop time and arm strength be able to get you to the next level?