Thought I'd post this piece of progress step by step in case it could give you a few ideas or tricks. (This mannequin doesn't have a back or full shoulders so the fit is a little strange on her).
Page 1
1. I learned in the past that just using pleather as straps is a big nono. It will stretch and your specifications will no longer be the same and your armor will begin to droop. I now cover nylon straps in pleather to make sure they're strong.
2. Since the material is a little thick, instead of pinning it I used small bulldog clips to hold the fold in place.
3. At the sewing machine all you need to do is remove them when they arrive at the foot.
4. Next I added a buckle and pinned the strap to the piece of my breastplate that curves around my back at an angle since I criss cross my straps for sturdiness.
5. Once all the parts were sewn to the main piece, I sanded where I would put glue, cut into the worbla to have better adhesion and connected the parts with contact cement.
6. To be extra extra sure I'd have no disasters at the con I like to use flat thumb tacks (these ones are nice because you can peel off the decorative sticker to make it perfectly flat). I pushed them into the fabric and into the worbla. Be careful it won't go through to the other side. I usually do this where I know itll go into a thicker spot.
7. (not labeled) To ensure better comfort I took my original pattern and cut out a piece of felt and glued it to the inside with hot glue.
The straps on the front of the plate are connected permanently to D rings.
Page 2
1. Every detail counts. I like to add extra eyelets just for look sand a little strap to hold the tail end of the belt strap.
2. Here’s where the criss cross is handy. I can now trust my breastplate straps to also hold my shoulder piece. I used snap sand D rings to secure the shoulder piece to the top of my shoulder.
3. So that my shoulder doesn't wobble I also added a strap that would snap in the back.
4. Same thing in the front. There's a loop with a snap to hold it from falling backwards.
(The straps in the front of the blade between the breast cups are purely decorative)