I have another sugetion, if it's possible(game engine):
- Until 1043 de iure capital of Poland should be Poznań(Duchy Oof Greater Poland), the capital of Poland was moved to Krakow during reign of Casimier the Restorer after pagan urpising and Bretislaus of Bohemnia invasion(1039) when he sacked Poznan and Gniezno
Second sugestion, strongly connceted with first
(1018 secenario) Mieszko could be Duke of Lesser Poland. There is no strong evidence but
- Mieszko was married with Richeza Ezzonen so he shold he his own court, Krakow and Lesser Poland was big, rich, prestigious prowince but also quite safe, far to the border of Germany
- Mieszko during was against Kingdom of Germany couple times commanded the army, he conducted independent campaigns on the orders of his father, most probobly he should command troops from his duchy according to feudal military organization
-His son Casimir was was associated with Krakow