Stick to the Early ones, the large one is a bit too plain for pavia, although is based on a picture from... 1512... if my memory serves... of Henry'VIII's dover defenses... so is actually period correct...
Early Ordinance is incredibly varied... so whatever you use will be simultaneously, fine and horribly wrong
Foundry made some nice ones that would be perfect... (i know i moulded them) and i bet OG have some too...