I sent an email to Roger at Zenith regarding the Mount Channel rivet count and the Rear Gusset for the Mount Channel. I later called Zenith and learned Roger would be away for a week. Give this delay I completed layout and cutout of 75BRS1-3 Rear Gusset, using the old design shown in the plans. I used 6061T6 t= 0.050" and matched the rivet layout and rivet could according to build standards and incorporating existing rivet line. The shop built parts appear fine but I will verify with Roger when I speak with him. In addition, I discovered I had received new Forward Angles 75F12-7 of t=0.032" when I received the Four Point Harness Option kit. I included a question to Roger about this.