Tried a new diamond bit in dremel. Worked so-so. Used it to score a line to cut. Then used a dremel EZ lock metal cut off wheel in air die grinder. Coarser cut but worked well. Cut short of line and used a hand file to trim up.
Used doubled up tape (stickly side out) to catch trimmings. replaced 3-4 times and vacumned up a bit in between.
