[Havan_IronOak]

I wouldn't say that I'm advising you to use unlimited fuel. It's your call.
The only time I'd use that option is with the Walther boat if I wanted to try the long distance missions.
You should use what appeals to you.

Remember that you CAN change difficulty settings anytime you're in port. So try a mission one one way the try another a different way.

My current game settings are as follows:
[Current]
LimitedBatteries=true
LimitedCompressedAir=true
LimitedO2=true
LimitedFuel=true
RealisticRepairTime=true
ManualTargetingSystem=true
NoMapUpdate=false
RealisticSensors=true
DudTorpedoes=true
RealisticReload=true
NoEventCamera=true
NoExternalView=false
NoStabilizeView=true
MPShowPlayerNames=true
MPShowTorpedoes=true

I do like to watch things explode, hence my leaving the external camera on, also I haven't bothered to master celestial navigation yet so I let the map update take care of that.