hi,
i read the Omegamania Thematic Auction book again, the 1st generation of the central tourbillon was launched in 1994 to mark the hundredth anniversary of the founding of Omega. the 2nd generation of the Co-Axial central tourbillon was launched in 2007.
i also went to one local library to look for any information for tourbillon watches. i did find one book published by Taiwan called Tourbillon Encyclopedia. i extracted relevant texts which mentioned Omega central tourbillon and summarized it for your information:
2 models for Central Tourbillon:
1. cal.2600/ 21,600vph/ 47jewels/ 54hr power reserve/ 1min tourbillon/ 38.7mm (available in 18K YG, WG, PT)
2. cal.2633/ 47jewels/ 54hr power reserve/ 1min tourbillon/ 38.7mm (available in PT)
1 model for Co-Axial central tourbillon:
1. cal.2635/ 21,600vph/ 48 jewels/ 45hr power reserve/ 1min tourbillon/ 42mm (available in PT, RY)
hope you find it helpful
stefan
ps: from the Encyclopedia, it states that so far only Omega and Beat Haldimann made central tourbillon.