If you haven't already tried Nigeis' Radar and TDC mod it is amazing.
http://www.subsim.com/radioroom/showthread.php?t=170944
I am currently running it with TMO 1.5 and it works great. I have prepared a short tutorial on using the radar to establish a contact's initial position, course and track here...
http://www.subsim.com/radioroom/showthread.php?t=172535
Soon I will be adding how to get an initial firing solution using radar and the 3-D clickable TDC (as soon as I stop having fun sinking things without map contacts on).
The beauty is that this moves SH4 from being just an attack simulator to a much more accurate radar simulator, plot simulator and TDC simulator.
In the words of the old commercial..."Try it... you'll like it!
JCC