I always thought the Seleucids were particularly strong in heavy cavalry. Yet they are lumped together with all the other early Successors just getting a few extra light horse.
In the later period they can field up to 12 heavy cavalry which seems a lot but their contemporaries the Attalid Pergamenes get 8.
Now according to Duncan Head’s Armies of the Macedonian and Punic wars the Attalids “…1000 horse took part in the Roman war with Macedon in 171. This seems to be the largest Pergamene force on record; the kingdom was never a major military power.”
Whereas under the Seleucid entry “… 6000 of these regular cavalry at Magnesia, providing the cataphracts. This is the highest strength found and must represent the maximum turnout of the settler cavalry.”
On top of this they also had the two guard units, Agema and Companions, each 1000 strong.
So, has there been more recent information about Seleucid cavalry numbers? Most previous lists (if I remember correctly) have been more generous (I have the figures to show that!!) but as I know perfectly well previous lists provide no evidence whatsoever

I am a wargamer not a historian and am genuinely interested to know the thinking from more learned types on this forum.