Using Evan Byne video guidance affixed the top skin. The composite seemed to need twisting a little to get it to fit evenly on both sides. Using the hole finder tool, the trick is to align the firewall flanges to be flush with the front of the top skin. Then drill the composite. Made a test fit of the dashboard. Not a bad fit but some gaps on top left side. Sourcing a suitable 120-degree pilot/countersink tool for the top skin (and empennage) composite proved tricky in the UK. I found one from a company on the south coast (BSA Regal Cutting Tools) that made one up to the size I needed. 1/8 inch pilot with 5/16 head (3.2 mm x 7.9 mm) that should suit the 3.2 and 4mm countersunk rivets. KAI calls for painting the composite black.
More