Throw a dart at a design Vod. There are seriously so many designs out there by several different makers that the question you need to ask yourself is, what kind of helmet do I want, does it have the feel I want for my Mando, how easy is it going to be to assemble, how much work do I want to put into it. What do you like? What kind of money do you want to put into the files themselves if any? Bells and whistles? Range finder-electronics for rangefinder? Sweet light and sound system for said helmet, padding?
Seriously though I’d pick a design that best represents who you are. Me personally I love the Pre Vizsla phase 2 helmet from Clone Wars season 4/5 with the sick ear cannons. Pick your face then find where to find it!