I assume you are referring to game options in the HPS system. If so a good question and I plan an addition to the War College but for now here is a summary of my opinions and descriptions of the various options:
<b>Optional Rules - Based on HPS Gettysburg 1.01</b>
My personal recommendation is to play the game with all options selected.
I find this produces a good balance between rules that favor defense and offense balancing off. I have listed the rules in what I consider related groups with explainations. This one determines whether the "new" Turn based game play is used. Turned based is badly flawed so I recommend always selecting this "On" for phased play. There is one exception. For multiplayer games "Turned" based play considerably simplifies play so I do recommend it for that.
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Manual Defensive Fire:</b> If on game is played in phases, if off game is played in turns (movement, fire and melee all occur as part of movement phase).
The optional Fire and Melee results actually consist of the game resolving the combat twice and averaging the result. It has the affect of moving the combat results more toward their median values. I prefer toning down the extremes and feel it generally produces a more realistic result. Also keeps you from feeling like one bad die roll decided the game.
<b>Optional Fire Results:</b> Average two results.
<b>Optional Melee results:</b> Average two results.
Combat modifier options including the Density modifier. Quality modifiers say that the Stonewall brigade ought to produce more casualties than say some green unit man for man because they are steadier and know what they are doing. I agree this should be on. While I haven't seen the density one in use yet I agree with the idea. Piling to many men in a single hex should make them better targets. The Flank Morale bonus is another new one that looks like a logical addition. This one will help encourage continuous lines rather than checer board defenses.
<b>Quality Fire Modifiers:</b> A/B units +10%, E/F units -10% modifier.
<b>Quality Melee Modifiers:</b> A/B units +10%, E/F units -10% modifier.
<b>Density Fire Modifier:</b> Fire against a target hex with more than 2/3 of the maximum stacking increased. This increase is proportional to the stacking value up to a maximum of 150% at maximum stacking.
<b>Flank Morale Modifier:</b> Morale of units increased by 1 for Rout and Disruption determination when they have friendly non-Leader units on both flanks.
I like the higher recovery rates because I find it actually encourages the player to not fight every unit. Managing fatigue becomes an important part of managing your forces. Without it, it is pointless to rest troops during the day since only at night is there any chance of recovery. With the rule daylight resting before reaching high fatigue is an important strategy for winning long battles. I include night fatigue in this since its part of managing fatigue although I haven't seen this one in action yet.
<b>Higher Fagtigue Recovery Rates:</b> Low Fatigue will have a fatigue recovery rate which is 5 times normal. Units with Medium Fatigue will have a fatigue recovery rate which is 3 times normal.
<b>Night Movement Fatigue:</b> Units that move during night turns accrue Fatigue based on the Night Movement Penalty parameter data value.
The next group are all related to isolation, surrounds and automatic kills. I believe they should be used as a group. I like the Isolation rule because it forces the player to keep his troops in formation and properly supported. That said, I also think it's to severe in its implementation so having the Weak ZOC and Partial Retreats on put some limits on it.
<b>Isolation Rules:</b> Causes Isolated units to have their strength divided by 4 when defending in a melee. Also Isolated leaders receive no benefit from their commanders during command checks. When an Isolated Artillery unit fires, it may become Low or Out-Of-Ammo. The Artillery unit will become resupplied when it becomes non-Isolated, unless the Artillery supply level for its side is zero.
<b>Weak Zone-of-Control:</b> Allow units to move one hex through enemy Zone-Of-Control per turn and to allow units to retreat one hex through enemy Zone-Of-Control.
<b>Partial Retreats:</b> Allow some units to retreat from a hex after being defeated in melee even when there is not enough room for all of the units to retreat.
The remaining are some cat and dog rules that fix various problems. Rout Limiting I tend to favor being on because massive routes just didn't happen as often as the game will cause without it. Victory Points for leaders just seems logical. Automated Defensive Fire is a must to play PBEM games in a reasonable time. Bridge repair is one that make some rather interesting changes to play, especially in Peninsul games. And, the Full Melee Defensive Fire is an attempt at fixing one of the worse side affects of Turn play (and only applies to Turn play).
<b>Rout Limiting:</b> Reduce the amount of secondary routing that occurs. Units in adjacent hexes undergoing a morale check receive a progressively larger modifier to their default morale. This modifier starts at 1 and is increased by 1 for each iteration based on a failed morale check.
<b>Automated Defensive Fire:</b> have the Defensive Fire Phase of Play-By-E-Mail (PBEM) games conducted under the control of the computer.
<b>Victory Points for Leader Casualties:</b> Victory Points awarded for enemy leaders that are killed, wounded, or captured.
<b>Bridge Limit and Repair:</b> Invoke the optional bridge repair and bridge limit rules.
<b>Full Melee Defensive Fire:</b> fire conducted by the program against attacking units in melee at full strength instead of half-strength.
MG. Kennon Whitehead
Chatham Grays
III Corps, AoM (CSA)