Thanks to the Don. I found this about Prize norm in difficulty, finishing time in the same ballpark as yours though I forgot to note it.
Quite a few "gimme" clues, but several that were tricky and even vexing.
FOI 1a, LOI 13 which required Google and was far outside my GK.
I also doubt I've fully parsed 11, though I see the key idea.
Also happen to share your CODs, as my 3 co-COD are 15, 26 and 29.