Didn't get to see your pics, (maybe in the Shed?). I'm hoping however that you used Stainless Pop-Rivets? Alloy will just sheer off in no time. Welding woulda' been better for lifespan longevity Vs Durability in a Work Environ'. Which basically answers your original Question:
Timber or Steel? Work Ute = Steel and Show Pony = Timber, maybe a nice White Mahogany and Blood Wood Mix, a Bit of Grey Gum if you like scribbly grain or Tallow if you like it straight?