All done for the day. On the right side, the first course was just set above the deck where it looked the same as the left side. Since the top of the brick mold is dead level and the gap between the brickmold and the existing siding was within 1/16" of being parallel, I measured down to the bottom of each course on the left and used that measurement to set up the courses on the right side. As with the left side, I kept double checking the distance between the new siding and the existing on top. When I got to this point, the gap above both sides was exactly the same and will allow for perfect overlap when I cut and install that piece in the morning.

I'll get the threshold buttoned up tomorrow morning as well.