LeeRoy stop making characters, find a few and write. Being a writer means you write. Of course you will write badly to start but the more focus you give to the craft, the better you become.
What is an assault class? They would have had basic infantry training and then their sniper training. Not sure how they would be any different than a modern scout-sniper team. Even if they are MARSOC or SOCOM teams they train routinely.