There is not much way around the TC problem. Every sim game can only be based on the principle of a player bubble moving around in the sim's world. Only once the objects enter this bubble are they calculated in real time and displayed as 3D objects. Anything outside the bubble is checked at timed intervals. So the higher the TC, the bigger the distance covered by these objects and increased chance of hopping the player bubble between two checks. Having everything calculated in real time is just impossible in relation with the power of our PCs.
So you're left with several styles of gameplay between which you must choose what you like most : play at high TC for fast patrols knowing that you will miss a lot but cover more distance in a given play time, play at lower TC so you don't miss events knowing it will take longer play time to finish your patrol, and of course alternate fast and slower TC following what you're doing (crossing the Atlantic or investigating a shipping lane). I am not sure you will see more action at high TC because you will cover more ground but you will miss many events.
As I am in no hurry I usually play SH3 at TC 128 and make a real time stop every 3 hours game time for a general check, crew management, look around and hydrophone check when in shipping areas. An average 4 to 5 weeks patrol takes me a week playing time at 3 to 4 hours every evening. When back in port, I leave the sub being refitted for a couple weeks while I go back to my dear flight sims or anything else. Then I start feeling the need for the next fix...
Sub sims on the dynamic campaign side have always been slow paced games where you must be ready to invest time. Otherwise you always have the single mission option where you have action right away.