I tried looking and I couldn't find an ETA which matched exactly. ETA 10 seems the closest to the Moskito one, so might be it.
The indexes are different for each game, so just copying them sadly won't work. That's also why we currently don't allow adding events from the drop-down in EDU as we'd need to find the indexes for everything all over again

Designer is a lot nicer as it has a file table for the DES and ETA file names, so you can use that instead.
Another issue with what you're doing is that the boss has commands:
Currently Ray1Map can't edit those, just display them. Then there are also the always commands which need to be added, but the game luckily works without them usually (if you forget the bullet always events for the Hunter he'll just not fire anything, so the game won't crash).
It's cool seeing that the boss health bar appeared at least
