Remove clamps. Trim lining to ribs. Sand flush to blocks. Mark edge with pencil, finish sand on flat surface (use long sandpaper on flat floor)
Drill holes in each end of template to fit locating pins on centre line, as close to rib as possible. The aim is to split the locating pin with the purfling. Mark hole locations on back on centre line, drill to match.
Tracing plate outline
Mount template on back, locate with pins. Trace along ribs with pencil, then highlight with red marker, then 3mm offset with pencil (use metal ring).
*** Don't forget to mark tongue location so as not to cut it off!
Mark radius extensions at middle bouts. Cut to outer dimension.
Do the same on the top, no tongue. Cut out both pieces - stay outside of lines!