Im in IL. Here is what we have. At least as far as my kid described it to me.
For the frosh team there is usually about 100 kids trying out for 28 - 30 spots. Two Teams (A&B). There is an optional summer camp prior to the students frosh year, so the coaches know how a lot of the kids play prior to the tryouts. Tryouts start first Monday of March. The first day is your typical pro-type tryout. Timed 60, 5 to 6 grounders, 5 to 6 pop ups, 10 swings in the cage, a few pitches, etc. From their they will weed out a few kids. The next day they spend a lot of time in the cages and throwing bullpens (for the pitchers). Weed more kids out.
By the third day the kids are moved into groups. Unknown to them, they are grouped according to the coaches perception at this point. I think they figure this out really quickly. The kids who already have made the team are in one group, the kids on the bubble the next group, and the kids who will be cut unless they produce something spectacular the last day in the last group. Everyone participates in the same drills, again typical pro-type stuff with additional hitting and bullpens. Each group is in the field-house separately. A(shoe-in) kids go first. They are moved through pretty quickly. C group next, again they move through pretty quickly, but not as fast as the A group. The last group to go are the bubble kids. They tend to spend more time going through the drills with this group.
The kids are then split into 3 rooms by their groups. A kids in one, B in another and C in the third. The A kids are told they made the team as a group. B and C kids are called into the coaches offices one by one and given their statuses. They either leave the building after the meeting (cut) or are moved into the A room (made it). For the most part kids do not see each other after being called into the coaches office. The last group to be dismissed from the school is the kids in the A room. They are not allowed to discuss their status with anyone until they leave the building. They are also cautioned not to be too excited (if they made the team) while they are leaving school grounds.
In addition they sometimes carry and additional kid or two for a few days. These kids are told up front that the odds of them making the team are long but they did show enough that the coaches want to see what they can do in a more "normal" setting.