I took a look at Harry's classes (2013-2018). All rankings are 247 composite:
2013 (5): Hunter Bivin (#97), Steve Elmer (#115), John Montelus (#152), Mike McGlinchey (#172), Colin McGovern (#193)
Hits: 2
2014 (4): Quenton Nelson (#61), Alex Bars (#109), Sam Mustipher (#225), Jimmy Byrne (#311)
Hits: 3
2015 (2): Tristen Hoge (#89), Trevor Ruhland (#462)
Hits: 0
2016 (3): Tommy Kraemer (#26), Liam Eichenberg (#80), Parker Boudreaux (#403)
Hits: 2
2017 (4): Robert Hainsey (#84), Josh Lugg (#120), Aaron Banks (#166), Dillan Gibbons (#374)
Hits: 2, 2 TBD (Lugg, Gibbons)
2018 (3): John Dirksen (#515), Luke Jones (#516), Cole Mabry (#716)
Hits: 0, 1 TBD (Jones)
9/21 hit rate (43%), however it could increase depending on how Lugg, Gibbons, and Jones perform this year. Boudreaux and Hoge started for UCF and BYU, respectively, but I don't count them as hits. 8 NFL players, and Elmer certainly would've been in the NFL had he not given up football. FWIW, Driskell said he was told that Nicholas Petit-Frere would've committed to ND on NSD if Harry didn't leave.