Charuks - and not only the feral ones - have been my faves from the days they appeared in the game. I am not hunting them so much for their tail-meat any more, tasty as it supposedly is and evidently plentiful, nor even their donations to my slave girls' skills either, despite they definitely improve almost every time there. I kill them to get my MC stronger, more agile and strong willed. It is amusing and mildly shocking to witness the amount of STR, WP & DEX those supposedly innocent beings can bring to my deranged MC.It is imperative to spend the time with him to gain that +5 accuracy. It doesn't go away on a daily basis, so once you have it it will remain for a while and then always fight in a way he gets a shot. Skip others so he would be getting a shot- Don't give coilgun to him, coil has a high recoil which lowers accu. So either stick with sniper or go with plasma.
Plus training sure does help.
I'm on a melee build while keeping Bud with a big gun. I like to hunt down feral charuks since having that 2000 hp of theirs means plenty of hits needed. Plenty of hits means plenty chance for criticals that increases skill. Usually when i visit the bay to sell guns i kill the two charuks as well.
With duraplate charuks usually won't be a threat, only if they really single out one person and only if that person has 75 or less HP. Otherwise it's just several skill level increase across the board from one fight.
Also the type of armor seems to be irrelevant there when the charuks miss by an inch every single time. I might be in error with this, naturally, since I am aware of my reckless habits and lacking sophistication. I dropped assids (asinine issids) all together after I briefly met with them in the legendary 0.8.1.1 game version. I liked mercs a lot earlier, I might mention. When they turned into assids those seem to crave tons of personal attention, training and almost constant entertainment from my MC, I have let them stay where ever they might find themselves.