Hey, nice work!
Just a heads up before you start fibreglassing the butt/kidney plate. Make the whole backside piece as thick and solid as you can get it! My first one was quite solid and I thought I'd be able to sit down on it, but it cracked, causing some delamination. My next one is going to be much thicker and I'll layer all of the fibreglass mat in one long session to make it really strong.
After six hours of trooping, standing the whole time, you'll long to take the weight off your feet, even for a few minutes!
Just for what it's worth.
Keep the photos coming, too. They are excellent.