Polish style saddles were the eastern 'rack' type. The hussar
lancers sometimes used saddles with high rears and fronts, but relatively simple saddles,
almost like modern English saddles, seemed to be the norm. Fancy horse blankets
often were made of Persian carpets or sometimes of animal skins. 
Rich comrades had a set of spectacular
'gala' tack and normal tack, although the normal tack could be quite fancy.
The plan is to have some items of horse
tack in camp. Above right is a modern 'pad' type saddle, similar to that on the winged
light cavalry horse below.
The modern saddle (easily available in US as reproduction)
that is closest fit is the McCellan cavalry saddle, also one type of the Universal saddle
seems good.
The final three images are fom the Book, Making of 'With Fire and Sword' (movie)
HorsesHorses selected for the artillery team would be high quality and enthusiastic, if calm and not exactly hot blooded. The mounted crew and dragoons would have lower-quality mounts, even older plow horses conscripted into service. The best mounts were for the cavalry, who generally provided their own, or were provided by their post's Comrade (their sponsor and superior). Unlike western heavy cavalry, hussars were mounted on hot-blooded animals, and at least the comrades had one or three extraordinarily valuable horses - often the most valuable things he owned.
See 
The Horse
Go to Patterns
Costume details and Domestic items,
e.g. buttons, belts, mugs, chairs
Article: Polish Costume in the XVII C.