Thank you, @Vincent_Vincent, for this. Although I managed to figure this out a while back when I was playing around with compiling an unfinished novel that had a prologue, it was a pain in the you-know-where. I’ve bookmarked this for future reference.
I saved my compiling-with-a-prologue adventure as a custom format, but knowing me, I prolly “did something odd that’ll haunt me later somewhere;” so I’ll compare my format settings with what you have here.