[Makinus]

With the caveat that i play exclusively single player, i notice that thugs do better if at least working in twos and with 4-5 bodyguards each.

It is also important to select the right bodyguards: ideally a bodyguard should have high HPs and/or protection, a shield also helps a lot, the rest is optional.

SCs, if well kitted, can work solo without much problems...

You also should not spend more than 2-3 turns in buffs (2 is better) regardless of reinvig, as the problem is not only the fatigue, but the lost turns before the thug/SC starts dishing damage.

Edit: a good strategy for using thugs is attaching another mage to the thug couple solely for buffs, i normally use those independent 1 nature mages for this role to cast small buffs on the thugs (nature has some useful low-level buffs)... I always equip them with some kind of bow, script the last spell as eagle eyes and leave them to fire at enemies...