Removed the excess amount of the longeron that was prohibiting me from getting the proper 5/8” spacing. With the spacing correct and everything measured and checked 100 times, I began drilling the firewall to the skins. This actually wasn't too difficult with a slow RPM and some boelube. After the firewall was drilled to the skin, I drilled the longeron to the upper firewall angle, making sure that the edge distance was acceptable. Make sure to use some longer AD4 rivets to keep the #30 holes aligned while drilling. I used some electrical tape to keep the rivets from popping out.