Not sure on the escorts I do not run the harder escorts mod myself and I find the OM AI to be as hard or harder than TMO.This might be because I am just used to the AI of TMO though because I find TMOs AI to be real bloodhounds if they manage to spot you other wise they seem pretty easy to slink away from.
Seems to me like the OM AI is a little smarter with depth charge patterns as well they drop 3 or 4 each one progressively deeper where as in TMO it seems they tend to drop more but much closer together so if they have your depth shallow they miss.In TMO I used to listen for an escort to start making a run as soon as heard the splash I'd would go to ahead flank to avoid the pattern.I have found this to be a very bad tactic in OM you do this in OM and the other escorts peg you hard.The hedgehogs show up in early 43 I think.
There is traffic in the Gulf of Mexico or at least I have found it there I have found ships off of Key West and also Tampa all along the Florida coast ships are there just more sparse.If they send me to east coast waters I get close to the coast and just sit and listen with the hydrophones manually because you can hear things the AI soundman cant I just slow tC and check every 30 minutes almost every night/morning I found a ship sometimes 3 within 20 miles bam,bam,bam that was off the coast of the Carolinas though.I real life a ship got nailed a mere 5 miles from Mayport Jax in may of 42 several got sunk about 20~30 miles below New Orleans during the war.
Not sure with your manual targeting problem I miss alot from longer ranges so I try to get within 2000m or less and try to get 90 I get hits about 80% of the time that way.Have looked at this thread? it goes into some detail about the optional mods for OM that relate to the TDC and other targeting tools:
http://www.subsim.com/radioroom/showthread.php?t=152590
Also Uboat.net is a great site on U-boats you can spend hours on there just going though the list of ships sunk.
http://www.uboat.net/
I have not messed around with any sound mod for OM myself.
I have seen some others have the free cam problem as well for me the free cam behaves just like it does in TMO
I just click on the screen and use the arrow keys and not clicking will move as well but more limited I think this feature was added but never mentioned in the notes.If you dislike where they make you stand in the control room(I do) there is an easy cure to this simply start from the bridge and right click you will move to the conning tower right click again and you are in the control room when you get to it this way the camera will stay in the spot you placed it for some reason when you F2 it does not while submerged just click on the conning tower and right click.
Flotillas
1st Kiel,Brest(II,VII)
2nd Wilhelmshaven,Lorient(XI)
3rd La Rochelle(II,VII)
4th training
5th training
6th St.Nazaire(VII)
7th St.Nazaire(VII)
8th Danzing
9th Brest (VII)
10th Lorient (IX)
11th Bergen (VII,XXIII,XXI)
12th Bordeaux (IX)
13th Trondhiem (VII)
14th Narvik (VII)
18,19,20,21,22 training
23rd Salamis (med)(VII)
,24,25,26,27 training
29th La Spezia (med)(VII)
30th Constanza (Black sea) (II)
Not sure on operation monsoon boats but they start in Lorinet or asia.