La solution ?
That's the problem.
When installing the ultra unit sizes, the unit size option in the shogun graphics menu is autpmatically set to "small" (of course this doesn't matter).
Try to set it to normal or something different.
Then the unit sizes will be normal again for sure.
And then try to set it back to small.
If it works, fine.
If it doesn't work, you'll have to reduce it manually by (I think) editing the preferences script (look for campaign_unit_multiplier and change the setting from 2 to 1).
Je ne peux cependant le tester car je suis en train de réinstaller mon jeu