Hi guys, thank you all for your answers...
Sooooo... I happened to unlock Bill Turner, level him up to G5 and find out, that I have LOTS of materials for G5 efficient mod... (Heatsing interlink being fortunately buyable on markets)
Now I have 4 C2 Plasmas G5 Efficient with various special effects + 1 C4 Plasma G5 Efficient with gimball/turet confusing effect.
Firing them all depletes about 4/5 of my wep capacitor (PD is G5 charge enhanced) and heat is very managable.
Plasmas though can be tricky - hahaha shame on me - I had to run away with 1% hull from Elite FAS NPC, which happened to have bursts and a cannon. He was manouvering like a god, evading my plasma shots as a jedi (boosting at the perfect moments), he was able to keep me in his sights and most of the time actually really hitting me.
I was also able to keep him in my sights most of the time, but the trailing gunsights were completely away as we manouvered and when I finally got the reticules on him and fired the plasmas, he magically boosted and plasmas missed him...
It was a nightmare of a fight and my confidence was seriously shaken ;-)
Anyway, 5 plasmas are viable and much FUN. Great agains larger and less manouverable ships.
Cheers! Karlos