Riveted the nutplates onto the forward and aft angles on both the left and right gear towers. I also rivetd the doublers onto the top and bottom section of the web and riveted the nutplates onto those for both left and right towers. This completes the modification and it took basically 7 hours total.
Nutplates riveted onto the one of the angles.
Riveting the backingplate onto the lower part of the web.
Here's the completed parts minus the attachment angles.