Level IIs are varied. My rules for ComStar forces: Aerospace are always paired, and non-combat vehicles don't count against the unit count. This gets to a mounted vs mechanized difference. I came up with this after going through whatever lists I could. The sourcebooks do not agree with eachother (Fall of Terra is completely FUBAR), so I made some executive decisions. It's worked well for me.
edit: I used an old version. I'm always tweaking. Note, this is for Level IIs. Level IIIs should be pretty close to the ratios in FM:CS.
Alpha through Zeta Level IIs contain decreasing numbers of ‘Mechs while increasing number of vehicles. These Level IIs are routinely used in offensive missions, usually with the vehicle and ‘Mech weights, armaments and/or speeds complementing each other.
Alpha- 6M
Beta-5M1V
Gamma- 4M2V
Delta- 3M3V
Epsilon- 2M4V
Zeta 1M5V
Eta is the standard designation for Infantry-light combined arms Level IIs. The infantry is APC or IFV mounted to keep up with the combat machines. Eta Level IIs have increased in number with the proliferation of Battle Armor, which increases the lethality of the unit.
Eta - 4M1V1I 3M2V1I
Low numbers of BattleMechs in Theta deceive many, but ComStar’s backbone is combined arms, and Theta is the most publicly visible Level II designation. With enough vehicles to mount all infantry, Thetas are the workhorse of any ComStar division, and are usually enough to respond to most situations.
Theta – 2M3V1I 1M4V1I
Iota Level IIs are the preferred garrison Level IIs for HPGs on planets that have a high chance of ‘Mech combat. The weights of Iota-IIs machines tend to be heavy and/or slower speed to better support the anti-‘Mech trained infantry which are often motorized or mechanized for fierce urban combat.
Iota - 5M1I 4M2I 3M1V2I
Kappa-IIs are the lowest Demi-Company designation that include the IFV and APC mounted infantry. Kappa-IIs are usually light weight raiding teams, and contain fast ‘Mechs and VTOL or hovercraft. Their infantry Level Is historically have not seen heavy combat, though the increased availability in Battle Armor has increased the offensive capability of Kappa-IIs.
Kappa- 2M2V2I 1M3V2I
Lambda Level IIs are all-vehicle Level IIs. Their missions vary as much as BattleMech Alpha-IIs. They support Alpha-IIs as easily and have as varied a combat profile as their ‘Mech brothers.
Lambda- 6V
Mu-IIs lack the IFV vehicle support or APCs to move their infantry components quickly, and so rely on personal vehicle support. Hover mechanized or jump infantry dominate, and wheeled field-artillery pieces are common. The Battle of Tuakkyyid saw many Mu-IIs be dismissed by the Clans, and concluded with Mus claiming many of the battle’s highest kill/loss ratios in the early days of the campaign. When overrun in the final days, though, Mu-IIs took higher than average casualties, and many Mus were disbanded.
Mu - 2M4I 1M1V4I 2V4I
The Nu-II is the preferred deployment to hotspots that do not require or cannot sustain ‘Mech deployment. Often, the vehicles are VTOL or hovertank equipped, but heavy urban vehicle Nus are common. On many backwater B-level HPG planets they are the only offensively capable Level IIs. Most non-MechWarrior Precentors are Nu designated. Nu-II urban and defensive abilities are noteworthy, while they lack some of the raw offensive power of the higher Level IIs, due to the lack of ‘Mechs.
Nu- 5V1I 4V2I 3V3I
Xi is the first of Aerospace and vehicle or ‘Mech integrated Level IIs. The Aerospace fighters support offensive operations of the 4 ground-combat elements and are usually light weight, but heavy or assault Xi-IIs are not unknown.
Xi - 4M2A 3M1V2A 2M2V2A 1M3V2A 4V2A
Omicron-IIs are a catchall for Level IIs than claim an aerospace lance and at least 1 infantry Level I. Omicron-IIs are usually found alongside Eta, Nu, and Xi Level IIs. Light ‘Mechs and vehicles predominate, and Omicron-II infantry are usually used as spotters for artillery equipped Level IIs, but Omicron-II machines can direct close air support of their heavy Aerospace fighters.
Omicron- 3M2A1I 3V2A1I 2M2A2I 2M1V2A1I 1M2V2A1I 2V2A2I 1M1V2A2I 1M2A3I 1V2A3I
The all-aerospace Pi-IIs are rarer in planet-bound Level IIIs, but are commonly found defending interstellar traffic and the Order’s spaceships. The lack of “boots-on-the-ground“ integration hampers their use in ground combat, but the arrival of Pi-IIs has ended many planetary assaults before they began as they swat enemy DropShips from the sky.
Pi 6A
All infantry Rho-IIs are varied in their composition, but are normally support for heavier combat machine possessing Level IIs. Rho IIs are the least offensively capable pure-Level IIs, and do not fire their weapons in anger for most of their existence. Their presence on many worlds goes unnoticed, and many support personnel are grouped into Rho-IIs for administrative use.
Rho- 6I
Sigma-IIs differ from Iotas and Kappas with the higher number of infantry, and perform similar defensive missions, though they require near-static positions as the lack of quick infantry transports limits their movement and offensive capability. Many Sigma-IIs have high numbers of jump infantry to offset their slow speed.
Sigma - 3M3I 2M1V3I 1M2V3I
Tau IIs lack IFV support for their mechanized or foot infantry and thus are garrison Levels IIs for low priority or mostly barren worlds that still see occasional bandit raids and require an attacker to invade a limited area. Most urban-combat Level IIs are Tau designated, as well as field-artillery IIs.
Tau – 1M5I 1V5I
Aerospace-heavy Upsilon-IIs perform defensive missions on planets that require a large Aerospace presence. They vary in size and speed, but have occasionally been used as support for offensive campaigns and defenders for many planets.
Upsilon 2M4A 1M1V4A 2V4A
Phi-IIs are similar to Upsilon-IIs, but contain an infantry component. The BattleMech and infantry pairing have limited offensive capability, though Phi-IIs are often found as a newly promoted MechWarrior Precentor’s command/honor guard Level II. The high numbers of Aerospace fighters are usually heavy machines.
Phi 1M4A1I
Chi and Psi Level IIs are the preferred Space/Marine Level IIs. Chi and Psi Level IIs train in capturing enemy DropShips, JumpShips and Space Stations, and are elite defenders of the Order’s space-bound ships. Psi-IIs are found as command units on many HPG A worlds, and those with large black-navy forces.
Chi 4A2I
Psi 2A4I
Omega-IIs are normally used in clandestine, high-risk or ROM sanctioned missions behind enemy lines. Omega-IIs usually contain the fastest vehicles available to the ComGuards (with advanced electronics) and high-flying light fighters with spying capabilities. The ability to quickly insert and extract the forward infantry elements necessitates VTOL or quick hovercraft.
Omega 1V4A1I