One of the difficulties that arises when using a grid is that if the unit of troops is physically large then the room for any terrain is restricted. In my opinion a unit occupying a grid space should not take up more than half the area if terrain is a feature. With this in mind, and given that my wargames going forward will be largely Portable wargame based, I intend to use Bob's basing convention for my 25mm Minifigs armies. This will be 2 x 3 figure bases for an infantry unit, 2 x 2 figure bases for cavalry and a gun with two gunners for the artillery. Foot command, gunners and riflemen/skirmishers will be on a 1" square base and mounted command on a 1" x 2" base. Using this system means that when a single unit occupies a grid area there will be sufficient room to deploy any terrain that is required.
I have opted for a square grid as opposed to hexagonal simply because terrain will be easier to both build and to configure on the playing area. At this stage though I am still debating about using an offset square grid rather than the usual chessboard style. This would combine the best of both worlds in many ways but I have not made any decisions as yet.
One of the other points that arose with all this concerns army size. Based on the size of my usual playing area - 13/12 x 9/8 grid areas - a good sized game can be fought with around 8 or so units a side. On occasion I have fought actions larger than this but not by much. As a good benchmark a field force of around dozen units will cover a variety of army selections for use on the tabletop and depending n the scenario being fought. It is always a good idea to have and army slightly larger than you would routinely use so that special units can be cycled in and out of the collection as required. Using the Portable Napoleonic Wargame as a guide I am thinking that my old idea of building up an army consisting of a Charge sized infantry regiment and a cavalry regiment with a gun battery would readily translate into 8 x 6 figures infantry units, 6 x 4 figures cavalry units and two gun batteries. That translates into a full strength army of 16 units under the Portable Napoleonic Wargame which is larger than the biggest action I have fought by 4 or 5 units. I would add a further gun and crew and some rifle/skirmish infantry to the mix meaning in total the whole army would top out around 66 foot and around 28 mounted with three guns.
As I survey the inordinate quantity of unpainted metal currently occupying the man cave this figures regime seems the perfect way for me to translate the ideas I have into a gaming reality and so that will be the next step.