For the ECW games so far we've been using Charge yr Pikes! rules with a few markups and minor revisions.
During the last battle in my Wiltshire campaign at Ramsbury we tried out an alternative in the rules for determining casualties from musket firing (by using a casualty hit table); these seemed to 'flow' better than what was in use before. So I'm currently in the process of writing up a set of 'house' ECW rules for our own use including the new method for casualties for melee and firing.
Meanwhile the two regiments of horse required for the 'Battle of Hungerford' have been prepped for paintingand are still waiting to be painted; I'm busy finishing of a few 18C bits and bobs at the moment.