I used garden edging on mine and it turned out great...until summer last year where the sun warped the shit out of them lmao. I actually saw a trick that I’m going to try eventually that looked great and keeps the shape of the edging.

Using a thin rigid plastic board (like a bread board) about 3/4mm thick you cut out little rectangles. Long enough for one end to bolt under the guard to the original flare holes and then another hole on the outside edge of the plastic tab to attach the garden flare. It’ll look like about 8 or 10 tabs hanging out of your guard once the tabs are bolted up. Then you bolt the garden edging to the top of each tab (using allen key stainless bolts looks great and professional btw). Not only makes them sturdier but also helps them keep their shape.