One more fit-trim and then the Big Cut. Decided the time had come draw the cut line and do it. Actual cut was anti-climatic as I followed the instructions to block the canopy sides, and tape the cut together as it progressed. Very little movement between the pieces when the final cuts were made. Used a Bosch 2.5 amp oscillating multi-tool, much quieter and less vibration than the Harbor Freight cheapo.
Deburred as usual and replace the two pieces back on the fuse to continue the fit-trim cycles.