Pure cavalry performs well enough, at least early on, it's just expensive. And seeing as most europeans don't get any boni to cavalry, you're paying quite a lot for not much extra bang (but you may have a bonus due to polish winged lancers, I don't know...).
Iirc, standard is to fill the front rank (i.e. your Combat Width) with infantry, then add enough cavalry to use your flanking: 2 early on (1 for each side), then later 4 and 6. Add some more infantry to increase stamina.
Artillery in the second rank add half of their pips, _rounded down!_, to the frontline, so when you get artillery with several double-pips, add some of those. ... if you can afford them.