Much the same. For IMG there are not full org level tryout days. It's about getting on a coaches radar, play against them, have film, and from word of mouth from other coaches and folks they trust to evaluate talent. Most of the teams host open practices and private workouts throughout the year. It's not just something you show up at tryout in late July. The ground work needs to be set before hand. Show that you can compete at that level, reach out to attend practices, look for opportunities to sub, etc.