Great references and research from all concerned and a typical friendly exchange of helpful info on this forum.
I always chuckle though when I see flame wars on other fora regarding wwi colours. I think if you calibrated the shade of a SPAD's apparent colours inside a hangar in natural light, then in artificial light, then outside on the grass at dawn, midday and evening, then yet again at 10,000 feet in bright sunshine and in cloudshade - why you'd end up with a whole catalogue of colour variations and that's before we consider the mixing of different batches of paint from different sources! So, my advice fwiw is not to get too hung up on exactitude: if it looks right to you, it's fine.
Sandy