We had to cut the first panel because we decided to bring the walls in just a tad because of the width of the welded on iron beams. Cutting a panel also means burning back the foam to the correct depth. Note: burning foam smells awful and we figure the fumes probably aren't fantastic for your health. Also, the tool gets and stays ridiculously hot, watch your extremities and clothes.
Wendy and I were super excited the night before building day. We got as much done as we could in preparation. Here's the wenderZ drilling holes into the splines to connect electrical chases through wall panels.