From waterloo 1815 and strelets you can find figures. Look at PSR under periods, napoleonic wars an there Poland.
The waterloo 1815 figures are in the stile of esci, but a solid base for polish infantry.
For strelets you must like their style of sculping. I have both sets with polish infantry an most of them i like, especally the faces.
Also you can find some very fine metall-figures from art-minaturen at schmaeling.de, esp. artillery.
You can also use french cuirassiers fore the grandduchy of warschau. The uniform is the sam, they have only other colours.
Good luck for your plans