I did one Venetian Vh/Vh campaign.

In garrisons I used 6 crossbow militia, 11 peasant crossbows and 3 militia cavalry. The Venetian militia cavalry is a great value, it is FREE in towns, $150/turn out of a town, has good stats and gets +3 valour if produced in a town with Merchant Headquarters. It gets 3 more valour if retrained in horse Guild Headquarters! It seams it earns valour very fast, in no time it has 3 gold chevrons. When besieged I sally out first with 6 crossbow militia, next with 6 peasant crossbows and when the AI runs away finish it off with the militia cavalry.

My siege army (sieges only) was a general, ~2 trebuchets or guns, ~6 Venetian infantry, ~6 hand gunners or Venetian armoured archers.

My field army (field battles only) was a general, ~10 crossbow militia, 7 spears and 3 militia cavalry. The Venetian crossbow militia is on “stand and fight”, they have good defence.