I was able to get some mobility out of my shoulder parts but essentially making hinges out of fabric that connected the pieces. I chose to disconnect the three main pieces, top, middle, and bottom, and then reconnect them with pieces of sturdy fabric and rondo. I get a good amount of wiggle front to back and they seem pretty sturdy.
In this pic I used jb weld to secure the fabric but I found that rondo held better.
That's the approach I used and it looks pretty good when they are mounted to the undersuit. Honestly tho once they are on, the really don't move around that much anyway.