Now that I have the original back roof pieces attached on the sides and the new roof piece attached in the middle, I can address the roof ridges.  The flat roof is now lower than the back roof, however, so I added a new 1/8" thick plywood layer to it.

I added a new partial row of shingles at the top around the entire roof.

By partial, I mean that the full height of the shingle strips wouldn't fit at the top so I marked and cut each shingle strip down to fit.

This includes the back.

The new row of partial shingles finishes off the flat top portion of the roof as well.

I had to reapply the sandpaper surface to the flat roof since I had added more wood on the previously finished surface.

I lapped cut shingles over the ridge for the front roof edge, but I want to see if corner trim will create nicer finish for the ridges.  I had used 1/8" corner trim on the portico ridge, but that's too small for the main roof ridges.  I have some lengths of various corner trim widths on order, so the ridges will stay unfinished for now.

the small corner trim used on the portico

But, so I can keep working on the structure, I painted the new shingles and flat roof to match the rest of the roof.

I'll do a quick sanding once the paint dries, and then I'll be ready to work on the chimney side.  :D