Miklos
The only person who I think might be able to help is Hermen Pol , who is a meticulous record keeper and has spent a lot of time at MMC going through their records.
Regarding the numbers, I wonder if the confusion arises between the 2 different capacity Fiat engines , the 1600cc unit was used in the 4/4, and the 2.0 litres unit in the +4. If both are combined perhaps the total could be 400+ units.
Regarding the split between 4 and 2 seaters I would be very surprised if the fraction of 4 seaters was as high as 90/122, the "normal" ratio is less than 1 in 4.
