[updated 31 Dec 2020]
For Shiloh your limit is 20 brigades, and you’ll have an easier time of it the closer you get to 20—all or almost all standard infantry (no artillery or skirmishers, no more than one melee cav unit) and 900-1,000 men per brigade is good. Your corps will take the lead and attack the Union right (left side of the map, from your perspective) around Shiloh church. For the attack on the Union left you will also control elements of Bragg’s and Breckinridge’s corps, which have artillery as well as large brigades. I think it’s better to emphasize regular infantry brigades for this offensive, maneuver-intensive battle that doesn’t involve taking serious fortifications.
You will aim for a day-one victory, which means going all the way north and taking the fort at Pittsburg Landing, and defending it against Buell’s first divisions that arrive late in the day.
Here’s one way to do it:
In the initial battle phase, on the left side of the map, you’ll start with the first ten of your brigades. Send them up the left edge of the map to a position where they are out of sight in woods but ready to run across the stream and hit the far end of the Union defenses on the hill.
When the remaining ten brigades arrive at the bottom of the map, have them advance up the right side of the map, on a broader front so they can push back any Union brigades or skirmishers in their way. Once this right-side set of brigades is engaging Union forces, have your left-side assault team cross the stream to the far left edge of the hill and move NE across the marshy ground and E towards the main Union defenses.
Collectively, your forces on this left-side map should greatly outnumber the Union defenders around Shiloh Church. Although you won’t be able to complete it in this initial phase, you should start maneuvering to crush Federal brigades in a mass slaughter against the east edge of the map, just north of the church. Avoid capturing the Shiloh Church flag early and cutting short the phase. You want to maximize your maneuvering/fighting time here.
In the second phase, you’ll control Bragg’s and Breckinridge’s units on the right-side map, along the Tennessee River. Send everybody up the left edge of this map, using your large brigades to roll over any Federals in your way. Along the way you’ll take the flag on the left side of this map. Shatter any Federals that rout up to the top of the map, but mainly try to establish a solid front across the top of the woods near the N edge of the map, all the way from the W edge of the map to the right flag. Don’t linger near the very top edge of the map because there are large Federal brigades waiting to pounce when the map opens up.
At some point, well before the phase timer runs down, the phase will end and you’ll resume fighting on the left-side map, and soon should start slaughtering trapped Union brigades on that map.
When that phase ends—as it will, soon—you’ll switch back to the right-side map again, which will open up to the north, revealing the Union’s Hornet’s Nest position. Use this phase to rest your units and/or bring them into position beneath and mostly to the left of the Hornet’s Nest position, and mostly in forest cover. Your late-arriving units, cav, and any other nearby units should destroy any visible remaining Federal brigades or artillery batteries south of the Hornet’s Nest.
When there’s about an hour left on the phase timer, start moving your forces up the left edge of the map, bypassing the Hornet’s Nest and then edging east, to get between the Hornet’s Nest and Pittsburg Landing (which is just north of the map edge). During this repositioning you will need to maintain a defensive line against (suicidal) Union attacks from the Hornet’s Nest area.
When this phase ends, the map will open all the way up and you’ll see that CSA is in an excellent position, having virtually annihilated the Union forces on the left side of the map and partly encircled those on the right side, and having a mostly clear path to Pittsburg Landing (the few defenders are hidden).
Take the Landing and guard against, or attack:
- Union reinforcements coming from all across the N edge of the map,
- Union reinforcements that will approach from the river side of Pittsburg Landing,
- remaining Union brigades from the Hornet’s Nest area.
Note that when the “finish” button appears, after the timer runs out and you are holding the Landing, you should NOT click on it. Wait a few seconds and the battle should end automatically. If you press that finish button, you will often have to go to a second day, now fighting a reinforced Union.
The basic strategy I have outlined above also works for CSA/BG when using the J&P Rebalance Mod. However, when using the mod, always check ahead for the numbers of units you can bring to each battle—those numbers may differ from the ones in the vanilla game.