Inspiration comes from the unlikeliest sources.
With the engine-mounts affixed, the thorny question of how to mark up the centres of the holes for the retaining bolts?
I achieve this by the simple expedient of dipping the base of a motor in a coat of paint and embossing a piece of paper with it, as seen at the ends of the rotor-arms here.
Something I last did around fifty-five years ago shortly after starting school, except with half of a potato.
Didn't imagine back then that I'd be using the same technique to build a flying machine.
And there was me thinking my education was wasted?