Did you think about creating a button for battles or taking an existing one for resolving the battles and give some sort of advantages.
Example : The Prussian player would have a button called "Oblique Order".
When using it there would be a test depending on Fred modifier, terrain in area(doesn't work or less in plain) allowing the Prussian player to bring most of his army to fight only a part of the ennemy (one flank) in the first rounds of combat, there would be another test to see if the ennemy could react in time to realign (like the russian at Zorndorf).
In the following rounds you can test if the center intervene more or less rapidly to intervene (in Leuthen the move was more or less broken by Prussian artillery) and later in the other flank doing an external march is coming in time before a collapse. It would simulate well how 20-25000 Prussian defeated a superior army. Of course after a Leuthen-like battle a modifier would help to realign rather to be taken on flank showing that the maneuver was known.
On a pure flank like Leuthen, the Austrian flank could bring less musketry fire because they are caught during the redeployment.
If they are able to redeploy they will be Musket fire exchange with less disadvantages (but still superior Prussian infantry).
I you failed the Oblique Order option, then well you know this is the old good Frontal or standard attack.
The Russians would have a button for either defensive positions or artillery barrage to show their effectiveness in these domains.
The Austrians would have Artillery barrage.
Some searches can be made for other Kingdoms and if no distinct tactics then Blank button.
I remember Nosworthy in his "Anatomy of Victory; Battle Tactics 1689-1763"
indicating that the French Army used his first column attack in the 7 years war at small scale like KlosterKamp or Sauderhausen. I will have to reread this and verify.
What do you think ? Is this impossible to do ?
It gives some immersion for possibilities offered to Kingdoms.