Trimmed edges to give about a 15mm flange, sanded bonding surface, marked up horizontal cuts, then drilled a line of 3/32" holes for cleco clamping then cut them into 15mm widths with the multi tool. Cleaned up the edges a little with the sanding disc.
Made up a test piece out of some foam/glass trimmings and fit 4 clips, 2 with flox, 2 with urethane glue, clamping with greasy cleco.