During the last session I mentioned that I might have to replace the right upper engine mount bracket due to an edge distance issue. The short answer is "yes" to that question so I have ordered a new WD-602-R and will be drilling the old one out during one of my future sessions. Fortunately at this point in the construction it only involves drilling out 12 rivets--could be worse.
Lots of other stuff to do while I wait for the new part to arrive, so I got busy riveting a couple of gussets that attach bulkheads to longerons and then attached and match drilled the upper aft skin. Following that I clecoed the forward upper skin in place and will drill it final on my next session. The upper skins will not be riveted for awhile, but after drilling them I will probably leave them in place while I work on some of the cabin structure. It really doesn't matter with regards to the construction, but I might as well keep them in place to add a little rigidity to the whole thing.
Gusset and upper skin detail
Upper skins in place
Aft skin drilled final, forward skin clecoed in position