Another difference I noticed from the Visual dictionary between Datoo/Kaplan and Rose's uniform is that Rose's boots have some sort of adjustment strap similar to jack boots. I believe Finn's boots also had that. I don't own the book yet so I can't post a pic of the boots in question.
This may have already been discussed and my search skills were weak while attempting to find it. Has anyone looked at building an Imperial Weapons Technician from Rebels?
Correct me if I'm wrong but this would be the base requirements correct.
Imperial Gunner helmet with gold imperial cog.
black balaclava
Light gray jumpsuit with Gold Imperial cogs on shoulders. Black detail stripe down the shoulders, arms, sides and legs. (Similar to 181st Fighter wing)