Thank you everyone for your input and thank you Nebfer for compiling the info from the FMs. That was exactly the thing I didn't want to do myself.
Nightlord brings up a good point. As Daryk points out in BT it's about 2 1/2 years of training before a crewman sees a ship, regardless of type. In my opinion it's pushing things to the point where you ask why there is a distinction between enlisted and commissioned officers. I'm inclined to stick with the distinction to show career paths.
The info Nebfer collected shows there's much more of a range of ranks commanding ships than I would've have expected. I can believe O5/Lieutenant Colonels and O6/Colonels commanding WarShips, they are valuable, prestigious assets but I cannot believe an O5 is going to command a DropShip with a crew of 10 to 20. I'm comfortable with O3s commanding the majority of the DropShips out there with crews up to 20, maybe 25. I can imagine a very valuable unit, such as an Overlord to be commanded by an experienced DropShip officer, an O4. But by the time an officer in the DropShip branch makes O5 I'd except them to be commanding DropShip squadrons, say about 4 to 7 vessels. Heck I would be OK with an O4 commanding a division of 2 or 3 smaller DropShips.
To clarify I am using the O ranks rather than titles because lieutenant and captain confuses many that don't understand the difference between army and navy ranks.
I contemplated on what rank system to use, I went with land ranks for expediency, though I did not think about the basic O series..
I also feel that with most of these ships that only have under 40 crew that a O4 or O5 let alone O6 is simply to high, and likely a symptom of the writer going with how it's done in the real world, ignoring the fact that most warships are in the 70 to 400 crew range, and are perhaps some what over ranked (In ww2 most Destroyers where commanded by a Lt. Commander (O4), post war they set it to Commander (O5)).
Overlords with it's 8 officers are some of the few Dropships that could conceivably be commanded by an O4 with out to much of a problem on crew size, As I listed in my other post I could conceive a O4, with a pair of O3s, and 3 or 4 O2s and one or two O1s being it's officers, when you have fewer officers it gets harder to justify having higher than O3, though it's doable.
A list of crews of most dropships officers/Enlisted
Avenger 3/12
Claymore 3/12
Leopard 2/7
Fury 2/6
Gazelle 2/8
Kuan Ti 5/20
Lung Wang 3/8
Intruder 5/25
Union 3/11
Hamilcar 6/30
Seeker 4/16
Nagumo 5/24
Achilles 5/25
Condor 4/20
Okinawa 5/5 (yes 5 Enlisted! all are gunners)
Hannibal 7/33
Triumph 3/12
Fortress 7/35
Hercules 5/23
Overlord 8/35
Vengeance 3/9
Excalibur 9/41
Rose 8/39
Behemoth 9/44 ()
Merlin 2/9
Overloard A3 8/54 (methinks this is an error, HMA has it at 9/45, as one needs ~11 officers for 54 crew and gunners, unless you can have 6 crew per officer?)
Nekohono'o 18/24 (an interesting officer ratio)
Conquistador 5/16 (15 are gunners)
Interdictor 5/22
Arondight 8/32
Taihou 4/19
Lung Wang P2 4/14
Vengeance DC PWS 7/27 (possibly 33, not sure if the 6 NCSS crew are counted as crew or bay)
Aurora 1/5
Castrum 20/90
Seleucus 5/16
Trutzburg 7/30
Gorgon 3/7
Duat 4/14
--Clan--
Broadsword 2/6
Confederate 2/8
Noruff 3/9 (8 of the En are gunners...)
Sassanid 5/25
Union-C 3/11
Carrier 4/13 (11 gunners)
Lion 9/40 (SLDF) 9/41 Clan (2 extra gunners, one less "crew")
Miraborg 7/33
Overlord-C 8/35
Titan 7/31
Arcadia 3/11
Mercer 4/16
Outpost 3/15
Isegrim 5/21
Aesir 9/37
Vanir 9/53 (again should be 11 officers)
Nagasawa 3/10
It seems that quite often their was a tendency to simply just use the minimum base crew. Even so most of these crews I would think are a bit to small, particularly for a military ship, even dealing with high levels of automation (in modern terms even the Leopards should be having at lest 20ish crew, most modern ships are going around 10-20 crew per kiloton of ship, with older ones (designed before the ~mid 90s) being around 30-40, with WW2 being closer to 70-100 crew per kiloton).
I've be playing around with a spreadsheet to breakdown crews into ranks, I'll share it here eventually. Of course it's just my opinion of how things should work but I am rethinking the rank ratios:
1. Ratings (E3 to E6), are the rank and file. Distribution would be top heavy because these people are the techs not leaders and their rank would reflect their tech abilities, not leadership skills.
2. Chiefs (E7 to E9 ) ratio 1 chief (all ranks) per between 2 to 3 ratings. About three E7's per one E8 and about the same ration for E8's to E9's.
Pretty arbitrary I know.
Still working on officers but I think the lowest commissioned officer rank normally seen in the fleet would be O2. O1's have just gotten out of their officer training and are spending a year or two in school to learn how to handle a ship. They're promoted to O2 once they are finished with this schooling. I doubt an O2 is going to command a DropShip but I can easily see them as XO's. O3's normally command DropShips up to about 5,000 tons. DropShips above 5,000 tons and/or with crew greater than 25 I'd expect O4's to be the most common CO rank.
For JumpShips I see O4's commanding most. They would be a mix of experienced DropShip commanders with additional training in hyperspace navigation and career JumpShip officers trained as hyperspace navigators and KF drive engineers from the beginning that have worked their way up the ranks.
Again, just my opinion.
I have no problems having small craft being piloted by senior NCOs as long as squadron leaders are officers.
Most Mechwariors are generally NCOs, though less info is available on what ranks are Fighter pilots, The battle of Luthien has the DCMS all be officers typically a Fighter Lance being a Tai-i leading a Chu-i (that's O3 & O2), Wolf Dragoons has one officer (a O2), leading a Warrant officer, the WD source book is largely the same but dose not indicate that the "non officer" is a Warrant or NCO.
Battle of Coventry has one officer leading 3 non officers in a flight, it dose seem that the Lyrans are running one officer to one non officer, 1st Lance is a Captain, other two Lances are Lts. (though sometimes their using a four ship lance...).
However theirs little that I know of that deals with fighter pilot ranks in relation to their orgs. But it dose seem that some factions go with all officers for their fighter units while others seem to go with some of them being NCOs/WOs (I would bet the Davions are just like the Lyrans, and Laio is like the Kuritans).