Here's the one and only regimental-sized force of cuirassiers in the English Civil War, Sir Arthur Hesilrige's famous London Lobsters (please click on the photo for an enlarged view).
This regiment was built around a core of 12 minis I swapped for with Saxon Dog, with the additional minis painted by Shaun McTague and finished by me. They are on my new ECW Batbases (which I really must get into the shop!).
The lobsters fought in deep formation, relying principally on firepower. At Roundway Down, they were overcome after a stiff fight. Their subsequent rout took them down a precipitous slope and many were killed; they were, later, reformed but probably without the expensive cuirassier armour.
In For King and Parliament, cuirassiers receive a +1 on their save when in melee or shot at (except by artillery!). I should explain that there's no need to use this many minis to represent a unit, it's just my megalomania striking (yet again!). On the table there will be intervals between the three troops.