Did you use plans for this or cut the pieces to length as you went along. I'd like to do the same upgrade, but if you have plans with lumber lengths and angle of cut it would be very useful.
This is something I'd like to do in the next couple of months. Being in upstate NY, its to cold to put my body weight on the fiberglass. I went to inspect it last month and the creaking when I went to step in made me nervous.