Probably around the max it’s supposed to get of 3,800 rpm
The only place I have seen any gear ratios/tyre size comparison to base it on is in Daniel Elberli’s book, ‘Citroen Traction Avant 11 and 15CV for beginners’ which indicates for an 11 Bl or 11B depending on tyre size either 109 kph or 105 kph at 3,800 rpm
I’m not at liberty to post further extracts from a copyright book though.
Familiale and Commerciale’s used a different Differential gear ratio so are slower.
For the 1st time Traction owner, the book does cover all the basics you should need