Now all done, with much head scratching and some reverse engineering. But I cannot parse or reverse engineer 10 across, so a hint would be appreciated. I also have 2 down as “evened”, just to make up the 12.
What a gorgeous puzzle - an inventive entry method with a constant sense of jeopardy that I might miscalculate while doing the “evening”.
My only minor gripe - I’m not a big fan of mediaeval Roman numerals, given that I have only ever seen them in Wikipedia.