I carefully traced one of the existing panel lines on the shield to get an indentation, and then proceeded to go through the indentation several times. Each pass grounded up a bit of the plastic until I reached the other side. Granted this does take off more plastic than what was originally separated on the panel line, but I didn't have a knife with me when I was doing it.
For the extensions I used the leftover plastic on the parts tree, cut them into several rods of equal length and glued them on the underside of the shield.
After joining the two parts, I put some of this Quikplastik stuff I got at Home Depot to cover the gap. I think it's plumber's epoxy putty.
The picture was a reference for me to see how it turned out. It turns out that I didn't put an equal amount, causing the top to have an extension and depression and the sides to be caved in. I believe I fixed it after these pictures were taken.
I added ball joint to the torso area.
