Thank you for your suggestions regarding thread color for the quilting. White it is! I came up with a system so the quilting would be consistent on all four gores. First, I laid the three layers together, interior, filling, and exterior, (which in this case are all the same linen fabric) traced the pattern piece, and stitched the three together on the outline. I wish I would have thought of cutting the filling layer to the exact size before I sewed the layers together. But I didn't, so I trimmed the excess allowance of the filling layer afterwards.
Then I made a template to start the quilting lines. I liked the diamond pattern from the quilting test so I cut a piece of paper to that angle and placed it at the top of the gore as a stitching guide.
Once I had the first X stitched I sewed all the quilting lines in one direction using the presser foot as a spacing guide. Then I sewed the cross lines.
I am so glad I went with white thread because you can see the damask design is still visible depending on how the light falls. I think if I had used colored thread it could have looked too busy.
I need to get those bone channels sewn so I can put this corset on and fit the gores!