I will say that if a PBR or PG event posts a "hot" number for your pitcher then it will only help him/her get noticed. My son went to a event & hit 86 on the gun (pitching) and that resulted in JUCO coaches contacting him. One coach wasn't even at that particular event, so I'm guessing he had no way of knowing if the gun was "hot". IMO hitting certain numbers IS important before coaches take notice (at least for pitchers anyway). Once they take notice then the discussions (and evaluations) can start. On the flip side I think if a high-school team is posting radar numbers those aren't considered by the college coaches as closely. Maybe that's a wrong assumption and posting a HS workout number will get noticed... I'd love to hear someone's experience with that.
Okay, I will bite. Pitchers velo numbers are the metrics that matter the most - but maybe not for a different reason than you think. The vast majority of college coaches that attend most showcase events don’t know as much as you think about how to evaluate pitchers. They are almost always the low man on the totem pole and are the least experienced - grad assistants or volunteer assts. Many of them have never pitched an inning in their life - so their first line of demarcation is something everyone can understand. Fastball velocity. And the magic number varies by program and level of competition but 90 is the most common. The first cull is made on FB velo (based on HC or PC criteria) and then the list is whittled down from there. But as I said earlier any school or scout will verify readings with their own guns.