@Cylestyne. Excellent DIY, in fact mother of all DIY thread. Your step-by-step detailed narration is impressive and reflects your passion for cars.
I have good experience with paint sealant (royal shield, a Teflon based sealant) and it has protected my black car's paint well over the past five years. Even a damp cloth is sufficient to wipe all the dust and dirt after driving in rain, which is otherwise impossible on a black paint, which needs thorough shampooing and waxing at least twice, or thrice a month.