Yes great pictorial and very well done Riaan. Just a heads up from years of experience of building many different types of light fittings. The fans you mentioned from RC components, ACDC components, Communica etc are not as durable under the heat and humid conditions above an aquarium. I would recommend the use of Papst fans as a replacement as IMO they outlast the ones from said companies.
Makes me wonder, lighting for the aquarium industry is over priced, but that’s just my opinion. If I had a degree in electronics I’m sure it i could build something that’s equivalent to a radion at a fraction of the cost. Unfortunately I don’t have a degree in electronics so I’m just one of those consumers that have to pay the asking price