Haven't had a chance to get to it yet. Have had guests up from the lower 48 (and a fishing trip

) that kept me away from the project.
I've been thinking about getting a steel 1-1/2" coupling to use as a donut dolly (has a bit more mass than the PVC one I have), AND backing that with a big magnet that I sourced from a speaker. Thinking that would allow me to locate the spot to hit on top "on the fly" for shrinking. I stopped by the plumbing shop yesterday, but it was closed.