Vodo's newbie questions

[Vodo77]

Ok, i'm currently running my fisrt campaign of SH4 (uboat add on), and even if i read a lot of topics in this forum, i still have a few questions, i will post them all here, and make another topic in the add on forum when the question is related to u boats.

SH4 on steam (i promise it's my last purchase on steam...), no mods installed (first run, i'll see what mods i want after, and if i have to buy a hard copy to install them).

My campaign is on 88% realism (i kept the contact updates), started at penang on uboat add on.
So let's start with 2 questions:

-about saving: i just want to make sure, it is recommended to save on surface, away from contacts and harbors, and not saving while on the map, right?
-also, i took the habit of marking all reported contacts on the map, does it cause any problem?

-more generaly, how should i deal with patrols? right now i'm on my 3rd patrol, and now i try to do as many missions as i can, if i run out of torps i return to base and end it, if i get a "no missions available" message and still have torps, i'll hunt a bit on my way back.
Am i correct or should i refit and be more agressive (on the first 2 patrols, i had like 50/60k tonnage and 3 or 4 missions done)