Prepared the skin by cutting the 4" access hole and the rudder cable exit. Also bent the forward edge using my hand seamer. That turned out better than I expected and didn't look bad.
Once the longerons were lined up and clamped I drilled the skin to them.
Finished the night by completing the fabrication of the rudder cable fairlead blocks. I used a Forstener bit in my drill press to drill the large center hole and a countersink bit for the mounting holes. Lots of builders complain about the smell and mess involved in this step. As a former woodworker it didn't seem to be a big deal. No different that drilling large holes in wood and making a lot of sawdust. The bit would get hot, but reducing the speed and taking your time it was no problem.