Patrick, please... call me Barry, only the Police and my Mother call me Mr Hilton!
Basing is irrelevant so what ever you think will be fine but as a general rule 15-20mm frontage per infantryman and multiple bases will make movement and calculation easier.
Combat groups of 4 as per the Napoleonic version for shooting and fighting.
I am beginning to get play test data coming back now. Artillery is deadly particularly against the smaller units.
I found the games I set up in the house to be very quick and very bloody so I am checking on the balance of a couple of mechanics at the moment.
Dave has mentioned the amalgation of units. Here is an extract of the draft text from that section to give you a flavour;
Infantry
Infantry units can be 10-50 models depending on the year and theatre of the war. A brigade must have a minimum of 2 units present unless the entire brigade is less than 800 men (40 models) when it can be fielded as a single unit.
Very small units of infantry and cavalry within a brigade can be combined into larger units which cannot exceed 50 models for infantry and 40 models for cavalry. They would then be known by either the combined names of all units or the brigadier.
For example: In 1863 the Federal infantry brigade known as the Iron Brigade is composed of the
2nd Wisconsin (200 men) = 10 models
6th Wisconsin (180 men) = 9 models
7th Wisconsin (400 men) = 20 models
19th Indiana (600 men) = 30 models
This could be fielded as 4 units with the noted strengths or
2nd/6th Wisconsin (19 models)
7th Wisconsin (20 models)
19th Indiana (30 models) or
2nd/6th /7th Wisconsin (39 models)
19th Indiana (30 models) or
other combinations.