Not really ébauches, Rather true cal. 360 in their double casing. The vast majority of those cased in by Voutilainen have not been presented to observatory competitions. The exact production number of cal. 360 is known. So is the total number of chronometer 27 made by Kari. You are not far off but it is not 20 pieces. For further in depth information you will need to read the article published on SJX- a must read.