My Boba Fett bucket is still on its way and I still have scrap foam ghetto-taped to the inside of my stormtrooper bucket. I just wanted to get an idea for what people prefer. Padding? Helmet liner? Other?
I like the hard hat suspension system. I have used that in both of my helmets. My Boba Fett is a scratch build & Jodo Kast is a DVH. Due to the room & the dome I used 2 different styles but still achieved the same affect. The suspension system keeps the helmet from moving around but also keeps it in the same position. I also like the comfort of it & there is adjustment if needed.
The Boba Fett helmet I used the suspension from a face shield & reversed the locking nuts from the outside to the inside. Epoxied the stud to the inside of the dome & then am able to screw the knobs that came with it & attach the suspension. Went with this cause of room in the dome.
The Jodo Kast helmet there was enough room to cut & fit the attachment area of the hard hat, trimming it down to a ring, to fit in the helmet. Used Loctite epoxy putty to hold it inside the dome.
Here's a pic of my method. I'm a residential designer and builder so I used something I just had on hand. It's 1" open cell foam normally used to close off the open areas under a metal roof's ridge vent. It's self adhesive on one side, so it's peel-and-stick.
My helmet is lightweight illustration board with a styrofoam dome. After some trial and error I found the ideal positions for the foam for me. It's soft enough to not be uncomfortable, but firm enough to hold the helmet in place except for a firm head shake. Open cell means air and vapor can pass through the foam, as the bubbles in the foam are connected to each other.