Smaller, but not skirmish, battle rules

[Conquistador]

Well, I am playing around on paper this morning with my 3 mm miniatures army plans for battles larger than skirmish in the ACW where I plan to use my deeply discounted set of rules, Mr. Lincoln's War for battles like Wilson's Creek, Honey Springs, etc. - basically, Missouri, Kansas, Indian Territory, New Mexico Territory, and maybe inland north Texas - where the numbers are lower than many in the East and between 1861 and 1863.

Since I am so early in this project as far as the miniatures being painted and based I am still open to people's suggestions about rules, battles/scenarios, etc.  The scale of the miniatures and the time/geography of the project won't change however.

Open to conversation about how to best do this project...

Edit:  The rules suggest (for 6 mm figures which I can place my 3 mm figures on) basing as follows:

Foot and Horse - 1/2" squares.  I was debating about using Litko 15 mm squares.

Artillery - 1" squares - if I use Litko 15 mm squares for foot I am thinking 25 or 30 mm squares.

Limber - width 1/2", depth as required - maybe Litko 15 x 25/30 mm rectangles?

Gracias,

Glenn