I didn't really have much to do. I had sanded down to the scribe line and then fit it flush to the rear spinner bulkhead so when I set up the ruler to pinpoint center, it was pretty close. A few minor adjustments. There's always the chance I'm off by a 1/32nd or so since I'm only eyeballing things but it looks pretty good. I clamped it in place pending a review of Section 5 on drilling opaque objects. The Section 5 in my manual does not have such a section so I'll check online.
