Well I only print my helmet, the rest of my suit is made from foam. But I'd be happy to share my settings for the helmet! Firstly, I print in PLA+. I understand that this may not be the most ideal material but I like it because it's quite easy to print. Speed and temperature will depend on your printer and your own tests for the material you're using. I have a CR-10 so I run around 80mm/s at about 210C. For a helmet I do about 20% infill but for larger props I will do 5-10%. My assault rifle for example is 5%. A good tip is to use 3 walls instead of 2 so that you don't get any ghosting, and so that your walls are nice and strong. I do support when necessary, and I typically print with a brim to to make sure that the print sticks to the build plate. I do a layer height of 0.2mm, though it may be beneficial to go smaller to get extra details.
What kind of printer are you using? Are you going to 3D print the entire suit?