I finished up the left side middle skin, for the most part and I have a little bit more to do on the right side. The bottom and aft parts will have to be done when the fuselage is turned upside down.
I almost got ahead of myself when I got to the -4 rivets on the lower front portion of the middle skin :
"Because of the difficulty installing the MSP-42 blind rivets at the bottom of the wing spar opening on left and right F-823-1 Mid Side Skins, they need to be installed now. Uncleco the bottom portion of left F-823-1 Mid Side Skin so it and the F-804H-1 Center Section Side Plate can be pulled away from the underlying structure enough to install the blind rivets (DWG 74)."
That's the instructions for the blind rivets on the front and rear side of the wing spar openings - I almost messed up and didn't put them in. It will be the same issue with two other MSP-42 rivets when I do the front skins - but the blind rivets only hold the skin and the side plate because the center section spar is behind that section. There isn't enough room for the un-pulled rivet to fit, until you pull the skin out a little bit and pull the rivets. Then the rest of the nearby -4 rivets can be driven. But if you drive the -4 rivets first, there is no way to get the blind rivet set without it contacting the spar.
All in all, I drilled out 7-8 bad rivets and replaced them. All good.
