There are often a lot of outside factors in my experience with high school ball. Some are simply coach’s rules, such as seniors make the team etc. I'd start out by looking at how he has awarded the roster spots in the past. You may find that a kid on the JV is better than one on the Varsity, but the Varsity is a senior, so the senior makes the team and plays.
The coaches at the two schools my son has played for, operated under that type of philosophy. This year will be interesting. We have around 17 seniors and a couple of Varsity underclassmen, that’s a full team before the tryouts begin, and I know some of the other classes have players much better than some of our rising seniors, so it will be fun.
Also, you can probabily tell who will make the Varsity based on playing time last year and positions need for the coming. I had a good relationship with one of the asst coaches and midway through one season, he said they already had decieded who would be on the Varsity the following year.
All that said, hit like a monster and field your position, hustle hustle hustle!