Because the brass screws exited the transom, I used an angle grinder to grind them flat on the inside and on the outside
to measure up the 'knees' for the corners, I started with pieces of 19mm DAR "Tasmanian Oak", and used a crude offset pencil to rough out the angle between the bow and the sides.
After cutting bevels for the two sides in contact with the boat, I had a piece that fitted.
I marked out the "knees" from measurements on the plans, drew a freehand curve, then cut with a jigsaw. These came up better than I expected.
Preparation for painting consisted of sanding back some of the worst overspills of epoxy...in hindsight, I should have taken the sanding of the spilled epoxy further, to ensure a good paint finish. (The orbital sander seemed to have the remarkable property of grinding off the epoxy before chewing through the plywood - perhaps because the epoxy is so rigid?)
I used a belt sander on the bigger dribbles of epoxy - no finesse there - epoxy and plywood are ground to dust equally!
Paint hides faults very poorly!