Speaking from personal experience of a 2017 going through this now, I would argue for the Showball camp over this HF camp if your son is Junior this year. A quick glance of the list shows more D1 schools at Showball, which if that is your son's goal, start with the D1's first and then move later into the D3's. Of course if his goal is to go to an elite D1 like the Ivy schools or the elite D3's, I would agree that HF would be my first choice.
The timing of the HF camps in June in Sacramento works best for a kid who just completed his junior year. We did that and my 2017 got a lot of interest from the D3's that were there. From what I've seen and experienced, that is about the best time to start looking at the D3's. No interest from D1s by Summer going into Senior year means it is time to change expectations and start looking at the other divisions. But Fall of Junior year is a great time to start getting a read from the D1's to see if you can generate interest over the coming year. Then by Summer you should have a pretty good idea where your son stands.
Another important factor is to remember that most Juniors will not have their ACT or SAT scores by this November date. For the academic schools, they might be interested in a high GPA, but they really get interested with the high test scores. Again, if your son is certain to be high academic and can get into the elite schools, then starting now with HF might be best. But otherwise, cast a wider net at Showball and then narrow it later if you have to.