If I thought this would really go anywhere, I would bang you one out in about one day and give you all the source files after I uploaded it to the HOST for you.
You want the equivalent of the central island from my Oceania terrain and you will need tiny islands off to the sides of the tiny map with an HQ for each country. I would setup an air spawn for each field to 7,000ft just off shore for fighters and 10,000ft for bombers. That way you can practice level bombing and get everyone into the air learning ACM faster. Or you can create a custom arena with my terrain "gunnery" and turn off kill shooter along with protect all objects. Then they all meet at A1 and go from there.
On gunnery:
7,000ft air spawn for fighters over A1.
12,000ft air spawn over water to jabo task forces.
15,000ft air spawn for level bombing pratice against a large visible target of hangers.
5,000ft air spawn over A1 for bombers to attack taks groups.
1,250ft air spawns over water to practice bomber torpedo and B25H 75mm against task groups.
1 GV spawn over A1 on a mesa to practice wirbel as close as 800 to drones. And a 37mm and 88mm.
1 4 mile long tank gunnery range filed with tanks and a 17lb and 88 on the firing line.
1 4,000yd calibrated gunnery range for tanks and a 17lb and 88mm.
2 CV task groups and 2 BB task groups sailing an intercept course for gunnery. You need to unprotect all objects from the arena setup.
1 CV task group sailing in tight circles for bombing practice.
PT spawns into the task group paths to practice torpedo runs.
200+ static tanks set out on ranges, in a tank town, and in and around a town to spawn out and practice seeing tanks hidden.
Shore batteries to practice against the task groups. You need to unprotect all objects from the arena setup. Wonder why the trainers don't tell anyone this gunnery training terrain is available from the custom arena HOST??....

You will need to set just about everything in the objects list to be down 5 minutes, unprotect all objects, and all the static tanks cannot be destroyed with AP shells but give off a very visible sprite when you hit them.
This is a Hitech setting that he won't change. HE rounds and bombs will destroy them. Static tanks are dumb objects so have no armor equivalent to active tanks. They are there to learn your GV optics and how AP and HE round trajectories are different. With killshooter off, your students can spawn tanks and shoot each other. The best way to use the tank gunnery ranges is to set the random spawn circle in the arena setup to "0".
I didn't think to create a script to set the arena setup to what I use offline for the CM. Right now I don't even remember how to write one.
The level bombing target is made up of bomber\fighter hangers and fuel bunkers set to the standard MA hardness so you have to drop the correct tonnage to destroy them. They are in the shape of a large target, very hard to miss seeing even from 30,000ft at the end of the 4 mile gunnery range in a large open space. Set their down time to 5 minutes and your students can air spawn to 15,000ft, and level bomb all night long. Still wonder why the trainers don't tell anyone about this. Players have wish listed for exactly this for about 15 years now. This will help new customers get the feel for everything that goes boom in our game. And they can keep using it alone offline.
This terrain should work fine since you can teach them everything in the game about shooting and blowing things up including each other.