If you decide to spray Rustoleum, You should ask or research about using a hardener with it. Times I’ve brushed it on without one, it scratches and comes off easily. SPI epoxy would be far better and their black has UV protection so is fine as a top coat. However, I have read the gloss level of it can vary depending on spray conditions. It’s low cost too, about 35 a qt. IIRC.
