Wonderful job so far, if you hit the triangle with sandpaper you will take off the remaining plating with the rust. There's a store called "the container store" don't know if they're east coast only or nation wide, got an under the bed plastic container, inside dimensions are 24 1/2" × 21 1/2". Big enough for 26" triangles and 22" grates. Soak your triangle in two gallons of evapo-rust, the rust will be knocked off and the beautiful plating will remain. Evapo-rust works well on grates also, you will see portions of missing plating where the flames made contact. That's one of the reasons why I switched to SS grates. Sent from my SM-J700P using Weber Kettle Club mobile app
Probly my best tip would be to keep the porcelain parts off the concrete/pavement.