The CORRECT size O curves arrived today. I had ordered a circle of 8, in O-31, and was sent 8 O-42.
Yay, these are now on the Halloween layout proper, and wired up. Loaded the MTH O engine with Proto Smoke fluid and gave it a test run. This baby smokes sooo much it filled the Foyer, and I had to open the front door for ventilation!
Missing only one piece of the Layout puzzle, still waiting for a Halloween station I ordered.