Pretty much finished up initial riveting on the lower fuselage panel. Most of the longeron rivets, and all diagonal and vertical channels, are 1/8" #40 rivets. The forward portion and last foot or so of the aft end are #20, 5/32".
I left the very ends un-riveted since I have to trim off the ends of the longerons to be flush with the lower skin. There are also some short L-angles that I need to confirm the direction before riveting, as they *might* interfere with the baggage compartment side channels.