Next I needed to secure the insertions for the gores. To do this, I pinned the two core layers together with the gore opening edges matched up. This is a perfect application for those bent pins I end up with by my normal habit of running over pins with the machine. They will hold thick fabric without distorting it, just like a quilters basting pin.
My gores were cut with a 3/8″ seam allowance, which I planed to trim to 1/4″ after quilting. Thus, I sewed the layers together 3/8″ from the fabric edge. This was close enough to the edge to catch my seam allowance (which is 1/2″), but far enough that I would be able to snug the gores in between the two layers later. I left the bottoms of the bust gores open because I was not completely sure what boning pattern I would be using, and I might have needed to insert a bone or two through that space before finishing the outline of the gore.
I removed all the basting, including the ugly-ass waist tape basting. The waist tape was now held firmly in place by the gore stitching, so I could get rid of that eye sore. The basting tape at the fold lines for the gores was easy to remove because I used contrast thread in the largest stitch my machine has.