Greetings from Australia................My experiences revealed the engine box mounting ply to be of very poor quality and replaced it. the fuselarge firewall is to thin and after mounting the engine it flexed too much. I added two vertical reinforcing ribs inside the firewall.
The rudder horns I cut off the suppied hinge to allow more throw and fitted new horns. Careful using the bare wire for the pull-pull rudder...best to replace with plastic coated wire to minimise possible radio problems from rubbing wires.
The fibre classing is generally first class......................the finished flying weight less fuel on my plane is 6.72 kg or 14.81 lbs.