Thank you Oh Wise Ones for your comments. Since I've never used a HofA or AofA before, I just picked one. The AofA solution appears to be easier, so I'll probably use that for the final code.
To help me undertand how both flavors of lol work, I think I'll try it both ways & benchmark each.
I bow to your collective Wisdom...........
Comment on Re^4: stumped on a complex data structure