Correct Back armor shaping

Ive took a look around the internet and Ive tried a few searches here and I cant find a good example of the shape of the back plate for the armor. I have the templates and have cut them out of sintra, shaped to the best degree I can but I still think Im missing the overall shape of the piece. I was just wondering if anyone had a few good pics of it.

i've been realy having trouble forming the back plate to.Doing mine in 1/8th inch(3mm) thick aliuminium.
In the end i've decided to make a cast of my back to work from as it's far to difficult to see if its ok and hold it in place at the same time.

thanks for the pic spawnfreak, it helped me get the shoulders into the right place. If anyone has a side picture, showing the arch of the plate, it would be much appreciated

Has anyone used the trashcan method for this? If so, what cans have you used?