I managed to add another six dismounted Union cavalry to the collection last night. This afternoon they fought their first action at Neil's place.
They fought dismounted at the earliest opportunity (because their mounted counterparts were at best a bit "undercoaty" and at worst au naturel).
For a first show they did OK - one dismounted rebel cavalryman for no casualties in return. Plus, when the artillery tries to activate and turn on them Neil's rebels threw a double 1 and promptly retreated!
Hurrah for the Union!